When enabling Advanced Optimus in BIOS, GPUMode-Fedora seems to treat it like NVIDIA GPU only was selected - therefore not allowing GPU mode switching via the applet.
Observed on Framework 16 AMD Ryzen AI 300 with NVIDIA RTX 5700 dGPU.
Update: I just noticed that even when Hybrid is selected in BIOS the applet would still tell me that NVIDIA GPU mode was active and that I need to switch to Hybrid in BIOS.