Most things work great out of the box these days. If you do your gaming through Steam already then it's the easiest it could be. Otherwise you can download some other platform like Lutris to manage your compatibility for you
There are definite exceptions though. There's this great website ProtonDB that tells you how compatible games are if you want to look before you leap.
Kernel-level anticheat can make some games unplayable on Linux. Basically, it's intended to detect cheaters, but it gives false positives on Linux. On the flip side, the software is super invasive, like once you're aware of how it works it will make you wonder why anybody would allow that shit on their computer. Probably because they don't know any better, but still. This is more of a problem with high budget PvP games like Call of Duty, so depending on your taste you may never encounter it
Hardware for the most part seems to just work through plug and play. However, if your stuff is highly customizable through software - like Razer Synapse/Chroma/whatever they call it these days - you may not have access to all the features.
Most Linux installers give you the option to just try out the OS in a non-permanent environment. So you could find a distro that appeals to you and then give it a test run without comitting to a full installation. It'd be a good way to see if there's any hardware or compatibility issues.
If you have an Intel/Nvidia rig and are thinking about gaming, I recommend pop_os! I've been using it for a few years now and I have no complaints.
"There's no way we evolved from monkeys, and I'll prove it: humans are good at holding bananas!"
Can't make this stuff up