I started daily driving sway during the transition from wlc to wlroots back in early 2019 (sway 1.0), so it's been 5 years.
Note that's since I got an HiDPI laptop in 2015, I have been looking at Wayland progress from the GNOME side for a long time, but not completly daily driving it because of some annoyances.
If you launch mullvad from the app icon, try you add to PrefersNonDefaultGPU=true (or false) in mullvad-vpn.desktop (cp /usr/share/applications/mullvad-vpn.desktop ~/.local/share/applications
If it is autostarted add it in .config/autostart/mullvad-vpn.desktop
Or add --disable-gpu to the in Exec : Exec="/opt/Mullvad VPN/mullvad-vpn" --disable-gpu %U
optimus/bumblebee is NVIDIA only, with AMD only setup everything should work ootb except some specific bugs (looking at you rocm)
Hello OP, on this kind of system GNOME should use the igpu by default and the dGPU only when an App "launched with dedicated graphics" from the menu, or with DRI_PRIME=1 from the command line. (Also some vulkan game can also select the dgpu)
If that is not the case this is a bug.
Are you using x11 or wayland, can you see what is using the dgpu with nvtop ?
We're talking about Qualcomm here, the company that made a deal with Microsoft to make Windows on ARM exclusive to Qualcomm SoC.