Please note that 15V USB PD is disabled on the 11th gen Framework on BIOS 3.09/3.10, not seen word on if it is the same for the 12th gen.
8.Disable support for 14V-16V charging. This will cause 15V fixed supply sources to charge at the next lowest voltage, typically 12V. We always recommend using at least 60W adapters with your Laptop. See USB-PD 15V mode issue - #48 by Peetz0r