iPhone powers up in DFU but won't charge even after restore

iPhone SE has started to shut down after charging to 100% then unplugging the Apple cable. Sometimes when it reboots it shows low charge %, sometimes it is high.

Thinking it was a software issue, I upgraded to the newest version connected to a Mac and now it won't charge at all.

I got it into DFU mode, iTunes recognized and restored it, but after it rebooted it still just sits on the lowest red battery icon.

The last time I could check, the battery capacity showed around 75%, but it seems like a failing battery not just depleted one?

The newer versions of software were rumored to cause power drain issues.

Could they have caused charging issues as well?