Need a "battery health mode" - prevent battery staying at 100% for prolonged time to prevent damage to the battery

I use the projector connected to power 99% the time. Only on rare occations, I disconnect it and use it elsewhere.

In other words, the battery is fully charged almost always. This is very bad for the battery.

There should be an option to prevent the device from charging when connected to power, and make sure battery level is around 60% (discharge automatically if needed).

If I plan to use it unplugged, there should be a way to just enable charging again.