Ok, thank you very much for the investigation. I tried to reproduce on Fedora 34 in VM and so far unsuccessful, the game runs smoothly for me even with mouse input. So could be something specific to your setup (Nvidia or smth). Although I do see some minor issues with mouse input on Fedora, like the game seems to not capture mouse pointer when it should - so something fishy is going on, will look more into it.
Sadly, it’s not the first time we get reports that Linux version runs worse than Windows one, which usually appear to be distro- and environment-specific (and I recall there’s been a few Fedora specific issues reported as well). Sorry about that, will try to change it.