Pro Tools Ultimate, HDX, UAD Octo PCI.
100 tracks of a live rock band, real drums, guitars, keys, massed vocals, etc... A decent amount of plugs and verbs, and my 11 year old Mac Pro 5,1 isn't even breaking a sweat while mixing.
Check out that CPU usage in the screenshot.
When Avid gets it together with Monterey, I'll see how my M1 Pro MBP compares.