Dunno, every single major problem I had in the last couple of years (including few month on windows) were caused by bad AMD drivers. Had to switch to wayland in large part to avoid that goddamn hw_done/flip_done timeout bug. And still, if anything tries to use VA-API it freezes the entire desktop with amdgpu_cs_ioctl reports "not enough memory for command submission". And it also recently started to not recognize the monitor plugged into it after booting, saying kernel: workqueue: dm_irq_work_func [amdgpu] hogged CPU for >10000us 4 times, consider switching to WQ_UNBOUND, so I have to re-plug it a few times for it to start working.
Nvidia, on the other hand? Not a single hitch so far.
Most ASUS-es use MUX chip nowadays. “Ultimate” in Armory Crate, “AsusMuxDgpu” in supergfxctl, and I think “high-performance” in system76-power, is dGPU-primary mode where it drives the panel directly, and iGPU just sits there doing nothing and could even be completely disabled, if so desired.