I did the thing! I installed Mint. After looking at my files and backing up what I needed (not much), I just nuked everything.

I have to jump through some hoops with Steam support because I lost access to the phone with my Steam Guard long ago. Not the fault of this install obviously.

After some fiddling with Bottles to run patch executables, figuring out how to give it access to my other drives, and running the game in Lutris, I got Ostranauts running. Getting my save into the right location was some trial and error, but it loaded. Everything runs smoothly.

I'll try for Grounded 2 after I get paid, as I'll probably pay for that one and get it through Steam.

Thanks for the input everyone! Everything is so fast and snappy, and, aside from getting rid of a lot of files I don't use, all the extra space Windows uses is now all mine! muahaha!

With your level of competence, I would go Fedora. Little bit of CLI fiddling, but 99% just works. GNOME / KDE / Plasma are available preinstalled if you want a specific DE.

I been gaming on it with three screens for many years, absolutely no issues.

Debian and KDE

Don't bother with Arch, it's too finicky, don't bother with Ubuntu it's too corporate

My go-to answer is Mint. It works on a ton of hardware out-of-the-box, it's interface is very easy to learn for anyone used to Windows, it's got a massive userbase so it's easy to get answers to any questions you might have.

I'm going to assume you've used the terminal before. Since you're not afraid of some fiddling I recommend Fedora or CachyOS. The desktop and hardware work out of the box on newer hardware and Wayland has great support for multi monitor. Get flatpak. Stay away from Nvidia.
I don't do pirated games but since you're not updating the game you can use Bottles to install non Linux software or maybe Lutris.
I'm running arch (on AMD) and just installed Fedora on my partner's computer (with Nvidia RTX 4050) both using Heroic and Steam for games.
Just keep trying what works for you. Linux is improving more and more.

Kubuntu. KDE is great and has a lot of QoL/productivity features that should exist in windows. I go from work to home and it's like a breath of fresh air.

KDE is very familiar coming from Windows.

Thanks everyone for the comments! Seems like Mint it is. I did some quick searching and it looks like the games I care about at this moment should be okay. Honestly it's just Grounded 2 (when I can afford to buy it, or if I decide to pirate it idk. I got a better job and it will feel good to buy things once I have more money) and Ostranauts right now.

I commented in another thread about the pain with the switch being all the backing up I'd have to do, but I'm realizing I really don't. Everything important is secure elsewhere. All my storage is games and such, all of which can be redownloaded and reinstalled. I'll just snag some save files and do the thing. Might try on Monday, my day off.

Anything in the Ubuntu family tree, Pop!_OS, Mint, etc would probably be fine. Mint is sort of a cousin of Ubuntu at this point. It still uses apt but has it's own software store. Most of the time you are fiddling with something, instructions for Ubuntu will work on Mint. I usually recommend Mint because it has a good out of the box experience like the @someone@hexbear.net said.

Regarding fitgirl repacks. I've tried with Armored Core 6 and Disco Elysian but couldn't get either to install correctly. I didn't poke around to hard though. You have vanilla WINE, Steam's Proton, the Glorious Eggroll fork of Proton and even Lutris to play around with when getting Windows games to run. I've had like a 98% success rate with Proton through Steam but that might be an issue if you are worried about DRM. Idk why anyone pirates lol. I do because I'm poor and hate capitalism.

I have been using Linux full time for a decade now and program as a hobby so as long as you aren't using, like, C# you should be fine. I use Codium which is the telemetry-free fork of VS Code and it's been a flawless experience. Eclipse and Java is clunky but it's like that on Windows too imo.