I've used Sony A7riv, A7riii, A9, and A7sii for astro time lapses. Some of those are here:
https://vimeo.com/brianinthecloud.
I initially render all of my videos at full native resolution, and then combine them together later with premiere pro, usually at 4KUHD, just because who has an 8K screen now? Also streaming at 8k is likely difficult for many users IMO.
I do love how much zooming around you can do when you've got 60 megapixels however, and I see that as the best advantage for shooting at such high resolution. Even with a stationary timelapse you can introduce lots of motion in post when you have so many pixels work with.