Battery drain SAME cell coverage

I've seen this asked repeatedly & topic closed out...However, NOTHING has changed to cause battery drain except updating ios 16!

I'm living at same location, etc.

I always have cellular data off, but since updating ios months back, losing battery & signal to point of SOS only.

To keep data costs low, I've only ever used wifi calling by xFinity (Verizon).

Anyone else with ios16, NEW cell coverage battery drainage & xfinity? Any suggestions would be appreciated.

I don't doubt it could be cellular provider, but I've got to have full grasp of facts in this situation before confronting CS @Comcast.

Thanks in advance!