I usually like to play my games without having a launcher open, but for some reason I can't seem to access the multiplayer features of NMS without going through Galaxy. Is Galaxy a requirement for this one?

See under System Requirements on the store page:
"Please note: The GOG Galaxy Client is required to access online features for No Man's Sky.
Multiplayer is available only between GOG.com users."

I know this is an old post, but the above stated DRM requirement didn't always exist. (but then the developers hid the fact multiplayer didn't work)

The game did not have multiplayer when it came out on August 12, 2016. It wasn't until July 24, 2018 when NEXT (v 1.5) was released that full multiplayer was added (except for GOG).

When NEXT was released there was a note that multiplayer was not available for GOG although they hoped to add that at some point in the future but no estimate for availability was provided other than a general statement.

Due to extremely negative response for being left out GOG allowed an option for a refund regardless of the hours played (refund was in the form of crediting your account) or one could wait for HG and GOG to create a way for GOG to support multiplayer. This was a limited time offer but had a generous period of availability.

Multiplayer for GOG was not available until December 19, 2018 and then only as a beta. Sometime after that (maybe January 2019) it was released for all which is about the time that Vulkan became a requirement (about the time of Visions or perhaps part of Visions).

I intentionally left out the timeline (about a year) where other platforms had bubbles or balloons showing that other players were in your game but you couldn't do much to interact with those (joint exploration added in Atlas Rises). The lack of support for bubbles was acknowledged but was never corrected.

when the game was released, it claimed to have multiplayer. It was the players who sought each other out found out it they couldn't see each other and have to force HG to say it doesn't have multiplayer. (we had to prove it before HG admitted it)

Much later when HG released Next and more lies about multiplayer, GOG did offer refund.

Fast forward to here we are now, to multiplayer in game, but with DRM. (in theory multi has not worked for me and kid despite both loading GOG DRM)

My point being, when the game was released it pretended to have multiplayer and their was no claims of requiring DRM. GOG only recently started noting games that had DRM present in their multiplayer games, like in the last year or so.

GOG was once all about being DRM free, so this game isn't the exception but now the rule.(i've got a long list of games purchased from GOG where multiplayer requires 3rd party DRM or GOG DRM where originally no claims of DRM years later they now do)

It's not lies for both NMS and GOG. NMS has multiplayer, and GOG has no DRM. And there’s an explanation.

DRM is about if code is encrypted/protected or not. Just try to install a new OS in a VM, install Steam and copy the game (all files you’ve already downloaded) and run: Steam will ask you to redownload this game, because encryption/protection key doesn’t match. It does nothing with multiplayer integration from the respective client. Steam do encryption afaik when you install a game, and when you copy the game, it technically known who bought it. GOG doesn't apply such things and this is "DRM-free". So as developer put the binaries to the server, you have exactly the same binaries without any additional modification. The DRM means server collect more statistics about you and your computer than without DRM.

If we speak about running a local server where the game wasn't attached to any server and everybody an host the one, these times are gone. reasons? local networks killed this feature. Back in a day you had a connection only at home via long wires (like null-modems or so), network configuration was painful and you often loose a connection just because a cat started to play with the wire. Later on you can attach Ethernet, and you have to remember that the A-B and A-A wires are actually different, go through some adventures with network configuration and.... what about a friend in a different building? other part of a town? other town? country? There era of services like dyn-dns began.

After a while the Steam/GOG/EA/... went out and started to provide an authorisation host, where it's known that: it's you, you have a game, this other account is your "friend" (in terms of the respective system, so it's confirmed from both sides), and then, some data can go in between in both directions. A bit later on you started to be able to match the game with a random person, which you see in NMS for an example.

If NMS will provide the multiplayer without GOG or Steam, company will end up with DRM like EA did where you have to log in into EA servers to have. It’s true even if you bought a game in Steam and have to run both clients for EA and Steam to play a game, even the EA client is builtin.

This isn't completely true. Digital rights management (DRM) is every tool, measure or technology for restricting the use of proprietary content. This may be by encryption, but can also include lots of other ways from data position measurement in conjunction with online activation, intentionally erroneous data files and the check if the error still exists (in a copy procedure, the error would be corrected automatically by the OS) to rootkits, checking command calls between system layers if an attempt of copying is made (and prevents these calls) and so on. The list of more or less stupid or hideous approaches is nearly endless.

As discussed here: https://www.gog.com/forum/no_mans_sky/company_unwated, NMS starts to 'enforce' online connection (not to confuse with multiplayer) by removing specific content if not online, even thou this content can perfectly work offline. This is in my opinion also DRM, as they push people into having to login to play (at least once - which taste like online activation, even if they don't call it this way).

The reason you have to use the client is not because of a DRM, it's because they're using the client to support the network components of the multiplayer.

No it's not. They don't need to support the network components for multiplayer.
Read Sean's post. The infrastructure for online multiplayer no man's skay is already included. GOG latched it on to their online system as a form of DRM. At default NMS is able to crossplay with any other service. NOT GOG's.
https://www.nomanssky.com/2020/06/introducing-crossplay-for-no-mans-sky/

As of the Next Gen update, this is no longer true.

All Quicksilver Exotic items including Void egg and Bobbleheads etcetera are now available in a fully offline game.

No need to run GOG Galaxy or use any save editors.

See this post

Can you confirm that the missing repeatable quests given by the five base NPCs have returned? Also, are the rewards offered for discovery and completing milestones (which can be done in off-line single-player) are restored to the game (they were part of the game I purchased, but were broken by the addition of the nexus) or do Ares and Helios still give you the cold shoulder if you don't have a constant online connection?

Because if you can't confirm that those offline single-player features have started working again, then the post you quoted IS still true, and if you CAN, then it's definitely time for me to update my game again.

I presumed Andreas was referring to the missing Exotic items in an offline game which are now available.
The details of the quests you refer to have never affected me so far, so I do not know where to look.
Best you do your own research on that aspect. Did you put in a bug report / save requesting restoration?

Perhaps you're right that the missing exotic items were the only items of concern to Andreas. However, the statement he makes is still correct even after the Next Gen update. There are apparently still game features which have been either removed or disabled (either intentionally or as a result of a bug) by the addition of the nexus. It is still a means to attempt to enforce an online connection by punishing the customers who choose not to maintain one, as it is my understanding that those features DO still work for players who play online, whether multiplayer or single-player.

I'm referring specifically to the fact that prior to the addition of the nexus, when entering the anomaly, you went to a room which had only Nada and Polo and a multi-tool selling device. Nada would reward you for reaching specific milestones while Polo would reward you for various discoveries. After the nexus was added, these two features were moved to Ares and Helios respectively. However, without an online connection, Helios will only do so once, and Ares will never do so. The repeatable quests I refer to are given approximately once a day, but only after each base NPC's quest line is completely finished. Each one offered a randomly generated quest once a day (or every few hours - I forget, since it hasn't worked for me for a long time) Each NPC had its own specific TYPE of quest: The Exovehicle NPC would "activate" a node somewhere near the base, and you had a limited amount of time to get there and plunder it for credits. The Overseer would request you to take a photo on a randomly generated world type. The Farmer would ask you for a supply of a randomly determined plant product, and so on. I recall that the Scientist and Weapons NPC also had such quests, but it's been long enough ago that I forget the details.

As to posting a bug report... no, I haven't. I've tried reporting bugs in the past - It did no good. The errors I reported back in 2018 are still in the game.

Sorry for the late response. I had to finish my master thesis which occupied most of my time the recent weeks. I am referring basically to the whole difference between the online and offline experience - whatever that includes. Because I never played online and this missing content is well hidden, I actually are not able to tell, what I am missing. A good example are these repeatable npc missions. I bought the game on Aug 1, 2018, and never had these. I had read about them in a wiki, but thought they where removed (or bugged) and the wiki not up-to-date, now reading that they actually still exist but only to online players bugs me now :). Not that I starved without them, but you know, I still feels just not fair - I paid the same as online players (well actually 50% off, but anyways).
That I usually referring to the exotics is because it's seemingly one of the bigger differences and currently the most obvious - but I must admit I don't really like them that much, even though reminding me a bit of the Lexx (but it would still not be the same without Zev of B3K). Let's see if they got a heart and involve us offlineers more in the future.
Freedom from the chains of the internet ! (posted in an online forum...)