Thank-you all for the kind support.
It's unbelievable how ignorant I can be on the matter.
My story continues as follows:
- I restarted from scratch using the same image (Armbian_20.02.0-rc1.037_Aml-s9xxx_bionic_current_5.5.0-rc6_desktop_20200205.img), reason being that in the s9xxx directory (https://mega.nz/folder/j9QSDQSQ#6WpasOlbZYIInfw6yo4phQ/folder/35ACSCjQ) there is no "Ubuntu 20.04 (focal)", as suggested by Steeman, so I don't quite know if any other image is actually compatible with my box
- I managed to install Python 3.8.3 in parallel with 3.6 and I built a virtual environment from 3.8.3
- then I installed HomeAssistant within that virtual environment and all seemed to work... except that the same Home Assistant did not install the Hass.io tab... and that's when I found out that Home Assistant and Hass.io are NOT the same thing (gosh! what a mess I put myself into!)
- plus I have got a bunch of other errors, inconsistently popping up (lack of Cloud, lack of Alexa, etc etc) every now and then
So here I am, I will be zapping the card for the third time and try the Docker solution as suggested by jeanrhum...
minor problem though: I have no idea what Docker is, and how it works and (unlike Python) I struggle to find good documentation.
Any suggestion for where I should start to learn this Docker thing?