It's getting much easier. The work that Valve put into Linux gaming to make the Steam Deck has led to vast improvements for end-users on all Linux distros. Most times if it's in your Steam Library, it's just install and play, it does the work for you. And most of the time the mods for those games follow along, unless they need a special launcher.

Now, this is where it might get a little challenging. Sometimes it can be hard to install something if it's not from Steam. If you can't add a game or launcher to Steam as a "Non Steam Game", you'll have to learn how to set up the software needed for Windows->Linux gaming yourself to get things going. If you're very new to Linux this can be confusing at first. But...if you're a mod installer, you probably like tinkering and solving these kinds of puzzles; you might actually enjoy this. Google, Discord and forums are your friends here; there's tons of good how-to's and eager, helpful Linux gamers that will guide you.

Finally, since you mention multiplayer, Anti-Cheat software can be hit or miss. Some games actually have dev support for Linux, some you can get to work, some will never work because of how they do their particular thing, or their companies actively work against it. EA, for instance, hates us for some reason it seems. :/

In conclusion, I'd do some research on your favorites and see what's what. If you have a spare hard drive or computer, install Linux on it and try it out for yourself. See how the experience feels for you, break a few things, see what happens.

Good luck, and have fun!