Nano 33 IoT rescue from the dead: No USB. No upload mode
Use the SWD interface and a programmer to burn the bootloader to SAMD.



source of the picture https://medium.com/@manuel.bl/arduino-in-circuit-debugging-with-platformio-9f699da57ddc

I had luck with Adafruit DAP library using an Arduino M0 to burn a bootloader to MKR Zero.