just for information I have developed a small codec to decode LoraWan frames from Tyness from Ewattch, it is not yet fully functional, but already decodes a good number of cases, not having the time to advance more on this project I but available for whoever wants.
https://gitlab.com/ctparentalgroup/decoder_ewattch_lorawan/-/blob/main/src/decode.js?ref_type=heads