Sounds like a hostage situation

Mine works, but I guess it depends on your setup. My main GPU is a 7800XT and my secondary is a 3090 I use for video encode/decode. OBS while streaming and recording simultaneously (if I ever have time), video editing and HandBrake conversions. It just works with EndeavourOS. I can do ray tracing on the 7800 XT but it's not something I care about in games so I always turn it off.

I'm sure if I ran dual 3090's in SLI it would be a pain in the ass but that's why I didn't try for that when upgrading my system, plus the power draw.

Multiple GPUs work fine in Linux. You can have one playing a game while you wait for the others to finish the real work.

I couldn't tell you about ray tracing, but it's been pretty painless for me to run specific apps on igpu/dgpu using switcheroo-control