

runs smooth like butter out of the box

I just used the first Proton version in my list, so GE is likely not required. Heroic 2.4.2 had an HTTP issue (bad address) so that is why some people are saying it doesn't work. Update to 2.4.3 and it'll work fine.

Controller bindings conflicted with Steam Desktop Mode
On-screen keyboard not working as expected
Can't install via Heroic. Installed via Lutris and Epic Games Launcher in Desktop mode. I had mouse clicks bound to the LB and RB so the game sometimes confused mouse and gamepad input. All in all, it runs smoothly, if you can work around the missing on-screen keyboard.

Program hangs on exit
I couldn't get it to install with Heroic Game launcher, so I ran Epic Game Launcher from Lutris with defaults. The game starts just fine and the game runs smoothly. The only issue I had was when trying to exit the game. Upon quit from the main menu, the game hung. After a while, a prompt appeared and I terminated the program with the prompt.
Works perfect OOTB
With the low framerate and audio issues (out of the box) this is not enjoyable. Next: tinkering with the proton version.
Sound/Music jitter and very low framerate