In a situation like that, Screen Time (built-in feature) may give you some hints; explore it to see what sort of information is available. Based on that info, since Screen Time gives a daily/hourly breakdown of app usage, you could conjecture what apps were used for how long at which times, although all this info usually can’t be determined precisely.

Replace the battery or pay to have it replaced.

iFixit sells good quality aftermarket batteries if you want to do it yourself (which I do recommend)

It’s impossible

I just didn’t get used to it, lol. Switched from iPhone 7 to 12 pro to se2 back to the same 12 pro and then to se3. The gestures all became muscle memory but having a notch and face ID instead of touch ID still sucked

How long will it last? I see it getting security updates for at least 8 more years (ten minus how long it’s been out) – the hardware can last far longer than that if you take good care of your phone.

1. Try a different charging cable
2. Try a different power block
3. Try a different wall outlet
4. Buy a new battery and replace it if none of those things worked

Restoring wipes the phone of all data, and since you’ve tried restoring already, it’s possible the data is already gone.

Was your storage full? Bootloops sometimes happen when storage is very full. If not, it’s probably some sort of hardware failure and it may not be fixable without disassembling the phone

Newer iPhones are water resistant and rated to survive spills like that (but no deep-sea diving experiences). Honestly, your phone is probably fine.

You need to make regular iTunes or iCloud backups of your phone if your pictures are that important.