This feels out-of-touch itself, like you haven't actually tried in years. Yes, to rebind your mouse buttons, you will have to install a piece of software, and tell it what you want each button to do... Exactly like you have to do in Windows. I haven't seen any janky work-arounds needed, and the software is a lot more responsive than I was used to in windows with the official logitech software. You don't need command line in linux any more often than you need to edit the registry in windows - your typical PC user can get by without it just fine and probably should stay away from it. As for game performance, there will always be variability here, but there is no hard and fast rule like "you will lose 20% performance in linux vs windows". Some stuff may not get along with proton or linux (big one is some of the "bad actor" anti-cheat stuff, as mentioned elsewhere in this thread that just won't work at all), but the vast majority is running great under linux - imperceptibly different, if it is even different at all. Finally, there are plenty of distros that will handle all the drivers you need with little to no input from the user. One of the primary selling points of PopOS is fantastic graphics driver support "out of the box", but they aren't alone - many make the process invisible or butter smooth.

I always love how many people that don't use linux to do 'X' thing, feel the need to tell people that do use linux every day for 'X' how bad linux is at doing 'X'... People going into windows specific communities and shouting about how bad windows is for 'X' or 'Y' task would be shunned to oblivion if not outright banned, but they come into the linux communities every day to tell us how bad linux is??