There’s this one on thingiverse and maybe a few more, though I haven’t printed any of these.
The charging module is actually super simple.
Just grab a TP4056 usb-c module from amazon/aliexpress, wire b+ b- to the battery, wire out+ out- to the remote. I just have the pcb hot glued into the bottom of the remote. I’ll grab a picture tomorrow if I don’t forget.
The only thing is it’s best to charge from the usb port of a computer because that’s 0.5A supply and therefore the pcb doesn’t heat up as much. If you charge from a more powerful source for an extended period of time then you might melt the hotglue.