I've considered using mine as a camera for a fixed install before, but the battery swelling thing is kinda scary. Doesn't help that a lot of modern phones don't seem to work without a battery installed, and that they often use ribbon connectors or other awkward setups internally. (so no just soldering a fixed power adapter to some pins)

Does anybody happen to know a software way of limiting charge to, say, 50%? I'm wondering if that'd help, as you'd at least be keeping the battery outside of the range where it's hardest to shove more power into it.

I haven't had any luck running any of the phones I've had open like that (a Redmi 9T and a few Sony phones), but it's worth a try.

You can probably solder the wires from a suitable charger to the internal battery connector pins if your phone still uses those, though you may also need a resistor in-line somewhere to trick it into thinking there's a healthy battery installed.

Make sure you get a proper charger for the task if you go down this route. Some people recommend just chopping up a phone charger, but putting 5V on a circuit that expects ~4.3V at max sounds like a bad idea to me.

...that's a thought. Now I'm wondering if I could scavenge a smart power plug/strip somewhere and do a bit of programming to automate things that way. A project for later, maybe -- ended up picking up a few old webcams and they're doing the job so far.