Ask HN: M1 MacBook Pro and 3 external screens

I currently use an Intel based MacBook Pro which supports 3 external 4k screens just fine.

I'm going to be upgraded to an Apple Silicon M1 (pro, not max) based MacBook Pro soon, and I've discovered that it doesn't support more than 2 external screens. It also doesn't support an external GPU, so I'm at a loss if there's a way to support my preferred work environment. The network access is very locked down, so using a network based screen protocol won't work.

I'm assuming that DisplaySync (not DisplayPort!) can't drive a 4K screen at any decent framerate. Are there any other solutions out there that I can try?