Upon switching, what should I expect to change?
Many things are very similar on Linux compared to Windows (e.g. Browsing, Steam). One big difference is that people prefer using package managers to install software (instead of downloading and installing it manually).
I’m considering Pop!_OS seeing as its praised for its compatibility and easy switching.
Pop!_OS is a nice distro and it should work well for you if you like the UI. There also many other good distros if you want to play around a bit. You can easily test them using a Live ISO.
What’s the situation with gaming look like? I know gaming on Linux has been a HIGHLY discussed topic for a while, is it easy to play any (non triple-A) steam game? I’m nowhere near involved in computer science, I’d just consider myself more stubborn than most end-users so I can persevere through some basic problems.
I'd say that you can expect almost all games to work. The main exception are games with anti-cheat that decide not to support Linux. In my case, there has only been one game in the last two years that didn't work (War Thunder crashes a lot more than on Windows). Playing AAA games is generally not an issue. You can check https://www.protondb.com/ for specific games.
GeoGuessr has required a subscription to actually play for a while now. I think they had a very limited Free tier until 2024, but it was not a great experience. The developers claim that they need to charge a subscription fee because they need to pay Google for the Streetview API access. To me, that seems plausible and would justify a subscription model (as opposed to a one-time purchase).
On the other hand, OpenGuessr seems to be a free alternative that offers a very similar game. That certainly seems like a better alternative if it's sustainable.