can't update firmware

The firmware on my Fenix 7s SS is 11.28 and could do with an update. But I can't!

I don't have home wifi and use phone data for everything. The garmin connect app is on the same phone, and for some reason I can't check for updates with the watch anymore, and I can't connect to the wifi the connect app is on. Argh.

Installed rubbish Garmin Express, and also no firmeware update. Only updates for various maps and the connect IQ store. How do I update the watch firmware?