big sur – How to upgrade to Big Sur? It hangs

I have been trying to upgrade to Big Sur, as some services just stopped working (kerberos).

Of course, the upgrade did not work (I would have been extremely surprised if it had worked).

So after I downloaded the 12.40 GB for the update, a window opened asking me to accept the license stuff, and then I clicked on continue to install it on the single harddrive in the Mac.

A popup then asked me for a password to install some “new helper tool” (???), and after I entered the password nothing happens. I restarted several times, waited almost 2 hours – nothing happened.

So what can I do? Wait a day? Wait a week? Code my own OS?