The device is in such a state by now that I decide it doesn't matter any more if I break the charging port. After all, what good is a travel light that can't travel because it only works when connected to a charger?

So I take the pliers to the circuit board again and apply some brute force. I pull and jiggle, changing the angle a few times and eventually, the board comes out.

Some cables are torn in the process, but it looks like someone with soldering skills could fix that. The charging port looks unharmed.

cable for the on/off switch

one battery cable