OSX refuses to support it because it eats into their monitor sales that use an alternative TB-based multiplexing protocol (which is only available on Apple devices, which are, well, not the world's best monitors, yet somehow the most expensive per square inch in a lot of cases).
All the various incarnations as far back as Ivy Bridge's TB2 should have working support in Windows and Linux. I have physically tested it on my MBPR from that era, and it worked, and I know of other people's newer OS-swapped Macs also working.
Lack of MST support in OSX has historically blocked 4k early adopters: 4k screens exported themselves as two logical displays due to 4k monitors coming out ahead of HBR2-capable controllers.
As for ARM-era Macs, as far as I know, they licensed a common ASIC block for their DisplayPort transceiver, which is also what AMD, Nvidia, and Intel have done. So, their hardware should still support it fine, but I have no clue if Asahi's work on the GPU driver has gotten MST to work.