So, having just beaten PoE2 (what a ride), I have set my sights on Kingmaker now.

Reading through the forum, I get the impression that I will need to min/max a ton, plan advancement paths for my char, possibly respect the companions, while utilizing at least 3 classes for each char.
Or fail the game.

Is that a correct assessment? I mean, that would pretty truthfully reflect the path (harhar) PFRPG has taken (which is why I dropped it in favor of 5e), so it wouldn't exactly come as a surprise, but it would be a huge disappointment.

Can't I just roll a simple char up and enjoy the game? And I mean, do so without setting the difficulty level to a silly low level and avoid feeling like all the victories are plain handed to me?

You need to specify what difficulty you are going to play on. For challenging and below anything goes so long as you don't actively harm your characters and have a half-decent grasp on the system. Hard is mostly the same, except you just need to understand what you are doing.
Unfair is the only actually somewhat challenging difficulty if you really know what you are doing.

Respecs are not needed at all. Story companions range anywhere from serviceable to very strong. I rarely use mercs even on unfair(and when I do I use only one), so it's surely not needed.

ill say min-max is likely needed to have an enjoyable experience especially if you a completionist. (some skills check etc for example can't even be possible without min-maxing or extreme save scumming)
but completing the game on normal probably is not needed

You can have 5 companions that are able to cover for literally everything. As to scumming dice rolls - that's up to you. Not needed to beat the game.

That reminded my my first take on NWN. I wasn't familiar with D&D, or any other RPG system for that matter, and after reading all the classes description I had that brilliant idea to create the most potent mage by multiclassing as a wizard-sorcerer. Oh, youth... Probably, min-maxing on the PC would make it harder for a completionist scum-saver, as it would make some PC checks impossible to beat.

Thanks guys.

That sounds reasonable. I'll go on installing then.

I'm certainly not going to play on Unfair, probably something half-baked in the middle of the field. And while I TRY to complete as much as I can (since I practically never replay games), missing out on things here or there is totally no deal breaker.

Again, thanks.

Ok, so....
I built a single class Ranger (cuz, that's just how I roll :P) and started the game. Starts out easy enough, the occasional reload here or there.

Difficulty Settings basically are: Gimme the TableTopExperience (TM).

After getting to Oleg's and then setting out into the wilds I start getting TPKed in every location relatively quickly. At that point it was just me, Val, Amiri and Linzi. So, I had to dial down a good bit and was finally able to beat a few locations.

Once I got my lineup filled with Tristian, Jaethal (and now have Octavia and Regongar to pick from as well) things turned around 360. I went back to my original diff settings, and besides a Shambling Mound near the big tree, nothing has posed any real threat.

We'll see how this goes as I progress further into the game.