@Unairedspecifics @PINE64 oh sorry for this late answer! I personally use a Jlink debugger (the one that is embedded on the NRF52-DK board. It's not that cheap, but it worth it! It's also possible to use a raspberrypi as SWD debugger. STLINKv2 also work but you'll need another debugger to unlock the memory of the pinetime dev kit.
Linux Geeks doing what Linux Geeks do..