iPhone 14 Pro, and I've been having issues since iOS 17.6.2 (currently on 18.1.1).
I've already gone through a factory reset (which helped for about 3 days), countless recommendations for hard resets, then iOS 18.0.1 helped for about 5 days, but since then it's been the same.
I'm not planning on getting it checked for two reasons: 1. the phone is already out of warranty, and 2. the fact that a factory reset and one iOS version helped for a while (3-5 days) suggests more of a software issue. I was planning on upgrading, but I don't want to buy a new phone that will lose a significant amount of battery health within just a few months.