USB has power but won’t recognize any device

Usb ports have different pins that connect to different independent rails on the logic board: power, ground and data, thus it can still supply power without exchanging data. There are 2 Usb ports on your Mac and you don't say whether both show the same issue..if that's the case it's very likely it's a logic board failure higher up in circuits of the logic board. If one works fine, check the pins of the faulty one from close and with a good light source, to check no pins are bent or oxidized. If you see dirt or oxide, try cleaning it with canned air and deoxidizing spray for electronics. Yet it might happen some final components have gone bad on the logic board for one single port only, each one has independent IC, resistors and filters.