As the minimal requirements for Raspberry Pi 5 is 5V / 3 amps, better 5 amps, this is a very unusual supply on USB-C with not so many options to find a matching supply (despite the recommended one).
To reuse existing supplies "in the wild", a 2 amp limit on 5V would be useful.
How can I underclock (and disbable features) on RaspberryPi OS to keep consumption in a 2 amps limit, right from switching on?
There are lots of 3A supplies.
The Pi5 will quite happily run on a less powerful supply (provided it outputs a well regulated 5V - which many aren't because they are designed to charge batteries where regulation is less stringent).
You do not need 3A provided you do not connect demanding peripherals and under clocking will not have much impact because the demand is managed by load.
Edit /boot/cmdline.txt and add maxcpus=N
Where N is in range 1 to 4.
