Normal USB cables are a pain to use with a soldering iron because they are too stiff and that makes the entire experience a lot worse. I also got a cheap powerbank from China that does 20V/60W PD.

A PCB etched to mate with a USB C cable eliminates the need for a connector. [CNLohr] then gave the board a three-digit 7-segment LCD display from Aliexpress, which can be had for around 21 cents ...