Mini USB-C PD PSU

Parts you'll need:
DPS5005 Adjustable DC Constant Voltage Power Supply Module
Type-C PD2.0 PD3.0 Fast Charge Trigger
Banana Terminals
XT60 connector
KCD3 Swtich
Rubber feet

All can be purchased from Aliexpress.

The switch is used to choose the input, XT60 or USB-C.
The square cut-out on the right is for an optional USB A output, you can add a little module if you want.

You'll need to do a bit of sanding as it's a tight fit. You'll also have to remove the tabs on the side of the screen and switch.