If you set GNOME session to be Xorg, and configure xorg to use
amdgpu, that
would leave mutter on TTY1 (ctrl+alt+f1) runnin on the intel card and your
session on the amdgpu.
Which sounds kinda nice?
*But you can edit the /etc/gdm.conf to run on Xorg instead and use the
amgpu.
Is there no way to do the same in Wayland ?