Thank you very much for your advice, they helped me solve the problem, now I am a "happy" owner of the 21H2 version! Your help has been invaluable.
On my own behalf, I want to add important information:
Less than 35 gigabytes of free space since the beginning of the update - NOT ENOUGH! I needed ~ 60 gigabytes (I took with a margin) of free space from the beginning of the update, for its successful completion.
If you have around 35GB, after download and "installation"(phase of update before the first reset)you will have less than 20GB of disk space remaining at the first reboot of the PC, which is NOT ENOUGH for a full update!
At the first reboot, you need at least 35 free gigabytes for a complete update.
As a result, out of 60 free gigabytes, 41 gigabytes are left. https://imgur.com/nzQtBka
Good luck everyone with updates, I hope someone will find this information useful!
Do you have 60GB of free space on the system disk?
Setupdiag.exe takes data from the last install error report. If you delete all error reports setupdiag.exe shows nothing. This means that during the last installation with an error, these features were present in the system.You can open oem .inf files with a notepad to figure out what these files are and delete them from the system. If those drivers for modem or WiFi, better to just disable this device before deleting drivers or windows can automatically reinstall it.