In terms of raiding on my M1 2020 MBP, it's a non issue. I travel with that laptop + a gaming mouse & a Keychron k3 (I think its the k3, whichever is the low profile one, I own several of their keyboards).
When I am raiding on the M1 MBP I have zero issues with FPS @ settings of 6 or 7. Some instances with more lava/liquid will dip the FPS slightly on 7 so I occasionally have gone to 6 (SSC comes to mind - a few of the rooms with dripping water mechanics are harder on the machine, but it is easily doable with a quick settings drop if needed). This is all to stay at or above 60 fps.
Turn off SSAO entirely. No matter the default setting, it's the single least efficient setting IMO in terms of impact to heat & performance. I have SSAO turned off on my iMac as well.
Speaking of the 2020 iMac w 5700XT, it runs WoW on my external monitor @ ultra wide 1440p @ 120FPS for near all content @ 10 settings except SSAO in TBC/Classic. I dip the settings a few points in retail to stay above 100 FPS, but not very far down at all.
This is all in MacOS BTW. I do not notice a huge difference in performance in Bootcamp on the iMac for this game. For other games, yes, but WoW client seems to be decently optimized for Mac since around Classic release when they enabled multithreading.