I have experienced issues with iGPU aswell. I have amd ryzen igpu enabled along with nvidia rtx 4070 and the amd driver crashes when logging in to windows. Some times the driver continues to function, some times it also crashes the nvidia driver. This all started after upgrading to W11 2H24 from 2H23. I have my igpu enabled because I have a 3 monitor setup, all connected to nvidia card but my av receiver uses hdmi as sound input so I use the free HDMI port on motherboard for sound only. This setup used to work before the upgrade (or should I say downgrade rather) to 2H24
edit: system specs relevant to issue:
Ryzen 5 7600X
ASUS TUF RTX 4070
ASUS ROG Strix B650E-F Gaming Wifi