So I still need to use Instant View with my docking station, got it. Been using that on my M1 air to drive 2x4K displays (the 30Hz display isn't that useful if I'm mousing around, though)
It's set up as 3 separate displays, from left to right: 4K30 (you can also notice compression in color saturation), 4K60 (main monitor), built-in display. Even at 30Hz, the second 4K monitor is good for keeping up documentation.