My Teensy 4.1 died, possibly by a short to the 3.3v output. It's also possible the 3v out might have seen 5v momentarily. It was running on a breakout board when it died, and a 3.3v-powered logic gate tied to the 3.3v pin died at the same time. Difficult to know without further info, but is replacing the voltage regulator IC (NCV8186AMN330TAG ??) on the Teensy likely to bring it back to life or is it destined for the round filing cabinet?