iPhone 13 mini overheating and losing charge very fast
Up until this week, my iPhone 13 mini has had stellar battery performance. However, the battery drain now is intolerable, if it's fully charged at 8am, it is almost at 1% by 3PM. I have it in an Apple transparent (silicone) case. The signal is very strong in my house, and no other phone or computer has this issue using the same Wi-Fi network. Yesterday I got the message that the phone was too hot (at 85% charge) and will need to cool down before continuing to charge. I unplugged it and this morning it now finished charging to 100%.
In the past, I could get 2-3 DAYS battery usage. I've also tried removing the case, as I've seen other threads where some people have mentioned this could be the issue.
How can I find out what is draining the battery this badly, without having to do a reset (which I hate doing, i have so much customization on my phone).
Thanks.
iPhone 13 mini