Sounds like your frying ports or overheating motors. Air-duster upside down can easily cool your motors but frying ports is irreversible
There is no good way to get a V5 brain right now except to send it back to vex and wait a few months to get a new one back (before you do this test EVERYTHING to make sure you haven’t made a mistake (check motor heat, motor ports, and share the code here to triple check that nothing is wrong. You do not want to not have a brain right now))
Here’s a thing that will help your ports on your brain and motors not die: