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.

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