No network (wifi or cellular) connection on iPhone 12 after iOs18.3.2 update

After my phone autoupdated to 18.3.2, it can now not connect to any network by any means.

It can't connect via wifi, other devices are using the wifi fine with no issues.

It can't connect via 4G or 5G

It can't connect via Usb bridging from my Mac.

It CAN get an IP address from the router on wifi.

Obvs have rebooted all network devices, even though it was running fine for everything else.

Not much I can do about the 5 G network.

Have hard rebooted phone, no change.

Have attempted to restore the phone and roll back to 18.1 from iTunes / finder, but can't because I can't turn find my off without a network connection.

For the third time now, it seems an Apple iOS update has killed my iPhone. It's so frustrating that they won't take responsibility for these mistakes, but they basically destroyed my property.

Any suggestion of things to try before I go buy another phone?

Thanks