Nvidia 390 drivers stopped working with kernel 5.5 and probably also Nvidia 340. I was unable to get Nvidia-390 drivers to work with new kernel 5.5. Other people look to have the same problems. I posted here: 5536 – The Nvidia-390xx driver module is not going to be installed on the new 5.5.5 kernel and other people confirm, there are more links to Nvidia forums.
If everyone with 390 and 340 drivers are unable to use kernel 5.5, what it will mean?
Give a nouveau driver an another try: Possibly its work is good enough now. rant: Either “the Nvidia liberates the drivers”, or “an LTS-Kernel in Fedora”
– seems like a “neither”.
I think Nvidia390 isn’t working yet with 5.5.x - you’ll have to stick to 5.4.x for a while.
I don’t know the game but if it’s complex, forget nouveau. Maybe consider a Radeon card, or hopefully Nvidia will soon open source their drivers (or contribute to nouveau).