Linux

Hey, others have already replied to a lot of things and you've already downloaded Mint (which is what I would have recommended also), so I would like to point out some things I always tell newcomers and some specific things for what you said.

First of all: Linux is not Windows is the hardest lesson to learn, there are a lot of things you're used to doing one way, but that doesn't make that way correct. The main example is installing software, looking on the internet and downloading a binary from a website is NOT how you do it, the example I always give is that of a smartphone, it's just as ridiculous to do in Linux than on a smartphone and for the same reasons. Instead use the package manager of your distro, that should work like the play/app store (except it's free), and if something is not there maybe you can add a repository to it, or maybe the program doesn't exist on Linux, only as a last resource should you do it manually.

Partitions and drives: Linux doesn't have the concept of a C: or D: drives, instead drives/partitions are mounted onto regular folders, so navigating through them is seamless. This means that if for example you were t mount the folder that contains all of your personal user data (/home) into a different partition from the root of the system (i.e /), you could format and change the system entirely without losing any personal data. This is very useful because it's very likely you will poke something and break stuff, with much freedom comes much power to break things, so being able to reinstall your system without worrying about your personal data is a good thing.

Drivers: mostly you shouldn't worry about drivers on Linux, unless your GPU is Nvidia, if so you should worry about drivers a lot. Nvidia's work best with the proprietary nvidia driver (instead of the default open nouveau driver), but the fact that the driver is proprietary makes it a pain in the ass to deal. You should 100% use it since you're gaming, but you should steer away from distributions that use Wayland (nevermind what this is for now) instead of X11 (Mint so far uses X11). If you have a Radeon you shouldn't worry about this.

I use my PC mainly for streaming

Be careful, afaik not all streaming software/sites are compatible with Linux. But that's not a world I dabbled much, I know OBS works excellently, but other than that don't know much.

downloading torrent files who's copyright you don't need to worry about

We all have torrent downloaders, for our Linux iso which are distributed via torrent of course

and light gaming. Usually just messing with New Vegas mods.

Iirc new Vegas is not on the supported list on steam, so you need to go to settings and enable Proton compatibility for all titles. I've never put mods so not sure how to do that, but you might need to read something before because the game is being run through a compatibility layer, so the files are not exactly where you would expect, and if you need to run a binary to find those files it needs to be in the same profile as new Vegas (each game creates their own profile based on steam ID, and each profile is in a different folder). Other than that New Vegas works perfectly on Linux, I've played it a long time ago, and now with the TV show I've started again.

Last but not least: Welcome!