Dave said in his podcast that there is no plant to work on / finish the uSupply.
It's sad.
To solve this problem, i took one of this cheap Power supply modules which are available at E-Bay, Amazon, Aliexpress,... put them in a box and connect it to my model plane 24V battery.
There are USB-C modules available which are handling the USB communication to get full voltage output from USB-C power banks / charging adapter.
Perhaps this would be an solution for you?
But be carefull.
There are multiple USB-C power standards.
Not every charger / power bank understands every standard and refuses to deliver full voltage.