5v/5A seems weird. Can normal power supplies even deliver this? One of the big benefits of rpi has always been to reuse power adapters and isn’t that all PD standard today?
Higher wattage PD chargers and powerbanks that I have here all work with voltages of 9/12/15 at 3A and 20V at up to 5A
No, it is not part of the USB PD specifications, and the Pi 5 is therefore not PD compliant.
The PD specs require a 25W device to operate at 9V 2.8A. A 25W charger is still allowed to offer 5V 5A and a 25W device is still allowed to prefer it when offered, but it is not allowed to require it.
To make it even worse: at no wattage are chargers required to offer 5V 5A. Even a 100W one (which is required to offer 20V 5A) does not need to offer it, and it is 100% PD compliant if it only offers [5V 3A, 9V 3A, 15V 3A, 20V 5A].
Higher wattage PD chargers and powerbanks that I have here all work with voltages of 9/12/15 at 3A and 20V at up to 5A