[Darryl Ramm]

What plugins are installed? (Not used, just installed).

Was this a full clean macOS install or is it a migration off another system?

System fully optimized? Try all that annoying stuff, just do everything.

What IO buffer sizes does this happen at? Sample rate?

What happens using headphone output thingy or any other Mac buil-in output , as the playback engine?

Standard troubleshooting steps should start with trashing prefs, trying new/empty sessions, trying built-in outputs etc. if you tried those already tell us what you did. Reinstalling Pro software rarely helps but everybody seems to like trying that.