It might be cheaper to get a power supply that supports later PD standards? E.g. IKEA is selling some cheap here for either 8€ (Sjöss, 1 USB-C port (max. 30W, up to 3A)) or 15€ (Sjöss, 2 USB-C port (combined power output of 45W, up to 3A, also on a single port)). Both support PD 3.0 and PPS (that's the fanciest PD standard that implements requesting arbitrary voltages from the power supply) They also stock nice and cheap USB-C cables. These power supplies work fine with USB-PD trigger boards set to 12V.