You're safe what comes to OS, 2.10 requires macOS 10.9 Mavericks or over. 2.8 files open normally in 2.10.
If you have 2.8.22 compatible scripts that you want to move over from 2.8.22, they will not work, or will be buggy.
But that's not a biggie, usually they can be fixed.
I've seen more complaints about the Mac version than Linux or Windows, and it's been awhile since I used Mac so I can't recommend if it would be better to use the normal MacOS Gimp from gimp.org or maybe the custom Gimp built by Partha. Just be brave and try out or wait for more opinions.
Btw, my fastest computer is Mac Mini 5.1 from 2011, and my Gimp comp is even older. Is 2014 old
The normal Gimp:
https://www.gimp.org/downloads/Partha Build:
https://www.partha.com/