I managed to make RNDIS protocol work following this extensive topic:
As I said in the beginning - no experience with any of these protocols that’s why it was a bit chaotic. I guess a need a composite device with the ecm and rndis protocol together where rndis is used by windows hosts and ecm by linux/osx hosts, but I’ll concentrate on using the rndis with windows for now.
The question of saving the configuration still stays kinda open, in the mentioned topic the solution was to write a small script that runs on linux start, is that the only solution? If yes I will just close the topic