It's not so much the batteries for me but the USB C port that has been my main issue and that damn humidity/water sensor that thinks that I've dipped my phone in water when I haven't
It actually is! Second time I'm having the subboard replaced. 3rd time I can request a new phone or a replacement by law. Still not ok for a flagship phone by such a large manufacturer
Try cleaning it. I used to have the same issue, and had to get the subboard replaced multiple times too, until I realized that mechanically cleaning it with something really thin works as well. Felt really dumb after finding out lol. The pocket lint can absorb moisture and then the sensor doesn't work properly.
That's part of the problem I have with this. Most electronics life cycle is gone before or around the time the battery is gone. Only people that abuse the batteries by over charging / full draining typically benefit from replacement batteries. -And this just mostly needs awareness.
The vast majority of batteries operated devices are stuff that in its use is going to be "abused". The hell is the harm in letting people switch out a fucking battery if that's the issue. Companies won't let people switch batteries out so they are being made. Apple have been fighting tooth and nail over repair shops