After many frustrating minutes in full gear, ready to ride but unable to connect to my iPad I have some hints which may help others -
1) it only connects to one device at a time. In one session it had connected to my girlfriends iPad and had to shut her Bluetooth down to get it to connect to mine.
2) Apple Pencil causes intermittent issues. Remove your pencil and disconnect it from Bluetooth.
3) connecting to the taxc app sometimes stops it connecting to zwift. Yep, so close your tacx app if you are having issues.
Remembering all this. Works like a charm :)