Good morning,
I have discovered a solution based on the information on another page of forum (Samd21 mini wired to rfm95 - #24 by Roelvdv) to use LMIC library (catena) to make a Lorawan node with Arduino NANO IoT 33 board. I saved some boards and a lot of time.
I am wondering how no one of helpers didn’t mention that page! Any way I am thankful for your support.
I put a video also next days in my youtube channel it could be helpful:
Make Lorawan node with SAMD microcontroller based boards using LMIC lorawan library - YouTube