I bought this game almost a decade ago and no matter what modern OS I try to run on it, it simply refuses to run. I get no further than the splash screen and that is it.

I even tried to use the Union patch, but even that failed to run.

I don't know what Union patch is, but the System Pack should help.
Otherwise I would suggest to look at pcgamingwiki.com how to get the game running under modern systems.

I have a laptop with 2 videocards (Intel HD something + Nvidia) and Windows 10.
Gothic 1 hung up on a startup (as a small black screen).
Solution from the last post in this thread fixed this issue:
https://www.gog.com/forum/gothic_series/gothic_1_working_on_windows_10

I managed to run the game, but after applying mods and patches, it refuses to launch or function properly.

I decided to purchase the Gothic Universe bundle on Steam since that game works seamlessly out of the box.

i've been trying for 2 hrs. installed a big ton of shit, doesnt even try to open. if i run without anything it crashes and makes me restart whole pc. im about to refund, ridiculous

For me there are mostly 2 issues:

The game only has a 20 % chance of actually starting. Mostly it crashes immediately and I have to use task manager to end the program so restarting multiple times is the norm, but once it runs there will be no more crashes. Just don't try to alt tab out of the game.

The framerate is usually at around 20 - 30 even with my system (Intel Core i5-4690k, AMD Radeon RX 5700 XT), but there are a few rare areas where the framerate tanks to the tens. Thankfully that is rare but it is disconnected from the graphics options. I still managed to finish the game just fine.