enricopit I'm a newbie , but I install steam from flathub and works perfectly flatpak install flathub com.valvesoftware.Steam com.valvesoftware.Steam.CompatibilityTool.Proton com.valvesoftware.Steam.Utility.protontricks
decembre-dhiver Very appreciate the help of every of you! Even though pretty much nothing has worked out, I'm still feeling support and I'm not alone with the problem =) As for @kaktuspalme and @Staudey I didn't try your tips yet, I can only test those later. Thank you, everyone!
kaktuspalme decembre-dhiver I think your problem is or was probably a multipart problem. The last one with Dead Cells I'm pretty sure is a problem with libbsd as I could reproduce on my system as well. But it should be fixed with the current update thanks to @Staudey But Nvidia Prime might also have been a problem.