Macs & Garmin play just fine. There were a few issues several years ago. They have since been resolved.

The Garmin Express (Mac) & Connect (mobile device) apps are free & do all the leg work of syncing, updates, routes, maps, etc...

If you have a route you want loaded, it's easiest to download from whatever source as a .GPX file, then open finder, navigate to the Garmin device & drag/drop it into the "New files" folder. The Garmin will process it to a route on start up. Or if a .TCX file drag/drop it directly into the routes folder, eject, power up & go ride.

The Garmin headunit will do a lot via Wi-fi for uploads, updates, sync, etc...but what you are doing depends on the ease of the process. The computer is not necessarily a necessity. Even less so if you have a phone with a bluetooth connection or home wi-fi.

My Connect app on my 2012 Mac Mini shuts down when Zwift fires up, but that's hardly worth mentioning. I'm sure it's related to a bash.shell "exit" command or whatever. I just leave it alone restart the app if I'm going to use it. (Which I rarely do.)