Ooooooh... now that is strange. It sounds like a firmware issue with your radio. Have you ever made it in to see if there are any new versions available?
Apparently there is, nothing specific thought, there is just “an update”
Trouble is Vauxhall won’t just update for free, unless specific issue. I’ve found someone online who can do it, for a cost, around £100, but doesn’t know what it will do.
If I knew it would sort it, I probably would, but it’s another cost, on top of the dongle, that isn’t guaranteed.
It’s listed under settings>general>CarPlay, I can connect to the server 192.168.50.2, although sometimes drops.
No one I know has same car, even on here I’ve asked to see if my car system firmware/software is different.