Recently got Sony Xperia 1 Vi as my backup and I blown by the quality of photos produced by it. In my recent vacation I didn't carry my Sony A7C coz of this awesome phone. Battery life is just amazing too.
I had the same issue few days ago. Tried everything to fix it and failed. Finally, I swapped the SIM to old phone, disabled RCS, waited few mins and then swapped SIM to new phone. After that RCS is up immediately.