UPDATE: after a bit of hacking around and the with the hints of the Telegram group I did manage to get into the bootloader.
The procedure actually works, BUT the small (and most important) bit that was missing is the following:

After shutting off the device, turn the device on pressing and holding the power button, wait MORE or LESS one second (the trick suggested by a user in the telegram group was to say "one mississipi") press and hold the low volume button until the logo appears (will appear also the warning ignore it) then RELEASE all the buttons and WAIT! Wait kind of 20 seconds, after that the bootloader will appear. Waiting is the most important part because seems like nothing was happening instead the bootloader is actually loading. This procedure works 100%, once you understand it will be super-easy to do it again.
I hope this will help!

Cheers!