According to the PlatformIO documentation, debug_init_break = should disable the initial break point. I’ll have to do some tests why it isn’t working.
The reset pin won’t make a difference. Unless I can connect a fully configured cable, I don’t usually connect the reset pin as it isn’t really needed. The chip can also be reset by SWD and JTAG commands.
My understanding is that the SAMD21 and/or Adafruit Arduino board support is part of the problem. They could change the USB code such that it triggers a USB reenumeration during initialization. That would get rid of most of the problems when running the board with a debugger.