Any ideas why Micritonic is not recognised in Cubase Pro 12 running under Apple native M processors?
It supposed to be AS native but obviously it isn't :-(

Hmm, I just updated to Cubase 12, I will try to install and run it on my Cubase laptop and let you know! Can't live without uTonic!

Cubase 12 in Apple Silicon native mode will not run VST2 plugins, only VST3.
Microtonic is currently AU and VST2 so until there is a VST3, you could either use a plugin wrapper with the AU running in native mode or run Cubase through Rosetta.

any ideas if and when VST3 support

Soon™