Yes there is a way to compare weapons, I don't remember the exact button but, I think it might be R3. I believe there is some prompt somewhere showing you how to do it in the sellers menu
Luipadre
"The disappearing dlss fg is a bug with steam input, turn steam input off and dlss etc will reappear another option that people say works is to disable you gamepad until in game then plug it in or turn it on and dlss will appear"
the bug is related to the controller, turn it off before launching the game, then turn it on in the main menu, dlss will be there