Here are the result!
giuliomoro get back onto Bela and execute /opt/Bela/usb1_network.sh

it execute with no output
giuliomoro run dmesg -w and leave it running in the terminal
Seem to execute normally with a lot of output
giuliomoro moment of truth: connect the USB-A to USB-A cable to the same computer where you are currently connected over micro USB
It show those 2 lines in the middle when I plug it

giuliomoro does a new network show up on the host?
Yes! Here is when not plugged in

And when i plug it via Usb A, Ethernet 12 appear

giuliomoro does anything appear in the terminal window where the process is running?
Do you mean on the ssh session?
giuliomoro can you connect to the Bela IDE on 192.168.8.2?
Unfortunately no, only via 192.168.6.2