Greetings,
Yes, Pro Tools 2021.7 is fully qualified with macOS Catalina - specifically 10.15.7. More information is here:
https://avid.secure.force.com/pkb/ar...tibility-Chart
https://avid.secure.force.com/pkb/ar...7-Release-Info
Standard Pro Tools now supports 256 mono or stereo tracks at all sample rates.
Pro Tools Ultimate supports 2048 audio tracks at all rates.
best,
Jeff