> Ironically Pro Tools is still not M1 native.

that does not surprise me at all, unfortunately.

> One cool thing in MacOS that Windows can't do is aggregate of audio devices/interfaces.

it does come at the cost of latency & jitter: fundamental issues that ultimately stem from having two separate audio clocks. and it's not really a specific limitation of windows, which tend to use ASIO for low-latency audio. there's nothing stopping a an aggregate ASIO driver from being written, i just can't imagine it'd be that useful, indeed, i've only ever used the macOS aggregate device a handful of times, mostly only to try it out.