Can I use or modify a Lyra development board to externally debug and flash Lyra modules?

No. It is not possible to use any of our Lyra (22) or 24 development boards for such task(s). This is not supported by the hardware. In this case, please refer to Which out of the box hardware can be used to externally debug and flash Lyra modules via the Serial Wire Debug (SWD) interface in development and production stage? for further information.