@pianopaul - SORRY, YOU ARE RIGHT …. at my old aggregate device (found an old screenshot …) there I had the 16ch Blackhole added, so never I had the virtual port problem … Now, when I add the Blackhole, GP starts as always now without creating or asking about virtual in/output ports. I think - this is a good workaround for everyone to work without the messages about virtual ports.
But the main idea of this post was to see if the link helps anyone with audio problems. Thank you!