I have experienced the same performance degradation after the recent update with an AMD CPU and Nvidia GPU. Someone on another thread pointed out that the upgrade of certain mesa packages caused this issue, and rolling them back helps. So I just downgraded the following packages and it went back to normal:
dnf downgrade mesa-dri-drivers.x86_64 mesa-filesystem.x86_64 mesa-libEGL.x86_64 mesa-libGL.x86_64 mesa-libgbm.x86_64 mesa-libglapi.x86_64 mesa-va-drivers-freeworld.x86_64 mesa-vdpau-drivers-freeworld.x86_64 mesa-vulkan-drivers.x86_64
On that same thread it’s mentioned that the problem lies with Mutter, which in combination with the new drivers causes discrete GPU to be selected as the primary one (which was the case for me too, since nvidia-smi reported all programs running on the discrete graphics). So you can either follow the instructions in the linked post to change some udev rules and fix the behavior, or downgrade and wait for a fix.