I removed the insides of a regular A500 PSU with 2.5A 5V line, and put a Mean Well RQ-50B into its case.
https://www.meanwell-web.com/en-gb/ac-dc-quad-output-enclosed-power-supply-output-rq--50b
It does about 4,89V at 105MHz with a USB thumbstick connected. Under full load the voltage drops a bit ...