macOS Big Sur deadlock update

This evening my macOS Big Sur requested a restart for an "important update". After macOS reboot, I get a screen made of a background with standard Big Sur wallpaper and a mid-size centred-view windows which is asking to me to connect to the Internet because this update cannot be done without access to a network.

I give my usual Wi-Fi connection, it didn't woks anymore: a popup with an icon representing a smoking appears telling me that the connection using Wi-Fi could not be established.

So I take Ethernet cable and plug it into my MacBook Pro and I tried to connect to Internet using Ethernet. Nothing to be done... and identical pop to the previous one tells me that connection could not be established.

The third and the last options is: "Cannot connect to the Internet". I choose this last one but a popup appears telling me that the update could not be done without Internet. I can choose between "Retry" or "Shutdown".

This I really weird and really frustrating. Today is Friday, tomorrow is Saturday and then is Sunday... I can't wait until Monday to call Apple assistance... I need my Mac BookPro fully operational urgently.

I tried to get into recovery mode (CMD+R at boot) and I see that I am to be able to connect to Internet. If I boot normally I get this hateful mid-size centred-view window related to this probably bugged update.

I have a good familiarity using Terminal, if anyone could give me some advices/tricks/workaround that require some command line... it will be ok.

UPDATE: I tried to run S.O.S. Partition on my OS Volume (not data volume), but all appears to be fine.

It is possible to get the rid of this update and let the OS to boot normally?

If you need it urgently, since you can boot into Recovery, can you create a new volume and do a fresh install of macOS onto that? Then you can migrate your files over to that new volume and delete the old one.