Keyboard
How do I know whether my keyboard is faulty or my Mac USB connection is bad
Mac Pro, macOS 10.15
Do you have a wired keyboard or a wireless. It sounds like your keyboard is a USB keyboard. If it is please reset the SMC 2-3 times back to back with no wired peripherals (scanners, printers, camera, etc...) connected and then retest the keyboard.
Instructions for the reset are in SMC Reset