2D Games slow down to 40 fps in game mode (NVIDIA)

Testing the bazzite deck nvidia image and 2D games slow down to 40 fps and stay there until randomly jumping back to 60 for a few seconds before falling back to 40. I haven't tested the games in desktop mode but I also have Arch installed on the same PC and the issue does not happen there. I tested Sonic Mania and Katana Zero and both exhibit the issue.