Cubase 11 no audio on Big Sur (Intel)

Just wondering if anyone has a system like mine, where Cubase 11 Pro is fundamentally failing? No audio in or out and plugins producing no audio.

This is a 6-core cylinder-style Mac Pro, with 3x RME Hammerfalls combined as an aggregate.

All working OK on 2 other DAWs. I have a Mojave volume on the same machine, which is hosting Cubase 11 OK.

Anyone else? Thanks!