After resetting my Apple Watch Ultra 2 (Erase all content and settings and unpair) and then repairing it with my phone, the watch is trying to automatically install the Mobile plan at the setup phase (and there is no option to disable this).
It results in a mobile plan stuck in "Waiting...". It's also impossible to delete it – it shows an "Unable to Complete Mobile Plan Change" error.
I have rebooted my phone and watch and did a factory reset for the watch three times already – the same result. I've also tried to reset the watch without a Vodafone SIM card inserted into the phone – as soon as I inserted it automatically installed this mobile plan to the watch, and it's again stuck in "Waiting...".