I have had this problem all along really with the Adafruit Feather M0.
PlatformIO does the reset, then says 'No device found on com9'.
It then leaves the devices with a pulsing red light.
Every time, if I upload a sketch from arduino, it revives it, and I can try again in PIO.
What I have found usually works, is if I hit the reset button on the Feather as soon as PIO says "forcing reset", but since the last PIO update last week, or certainly since me trying to use it tonight, it's pretty much hopeless. I've spent about half an hour now trying to upload stuff. Succeeded once or twice, failed about 15 times, including going back to Arduino IDE to load 'something', just to get out of the pulsing red light thing.