Ok, finally got the damn thing working on Home Assistant Supervised. Once I learned the basics of Docker, I first installed Portainer.io and once I understood the following posts: (Hass.io remote z-wave module with socat/ser2net?), (RPi as Z-Wave/ZigBee-over-IP server for Hass), I was finally able to make it work.
Many thanks for everyone that helped me before (@tom_l, @123, @Silicon_Avatar), as you put me in the right direction.
Also, thanks for the authors of both posts above (@brianara3 and @luma), and specially @quasar66 and @ascent for their answers in the posts above mentioned, which finally led me to the desired results.