Hi Sumit,
Out of several different machines I have only one that was having problems updating KB5012170.
All windows 11 machines did that update without any issue and so did a Windows 10 Laptop that still has Legacy Bios.
The only one failing was the Dell XPS 8700 (UEFI and Secure Boot) running 19044.1865 and trying to get next updates.
It was hanging and freezing at 96% installing of KB5012170 when W.U. first tried the update.
Every subsequent attempt failed downloading with error 0x800f0900 and was blocking any other updates from W.U.
Also, KB5012170 first attempt left corrupted files that could not be fixed by "sfc /scannow" nor by
DISM /ONLINE /CLEANUP-IMAGE /RESTOREHEALTH
as I previously mentioned.
Since I did not want to do a clean install, I finally tried the suggested solution from this other thread:
KB5012170: Security update for Secure Boot DBX: August 9, 2022 - Microsoft Community
As suggested, I cleared the existing Secure Boot keys and set back the factory defaults, saved the changes and exited BIOS to reboot back to a freshly restored image of 19044.1865.
Then I installed KB5012170 offline using the .msu file downloaded directly from the MS catalog, that finally worked without hanging or any other error.

After that I was back in business, I could get all the other updates offered by W.U. and finally got the system up to 19044.1947 without any further issues.
Ran "SFC /SCANNOW" again and this time it ran clean. No more corrupted files. 👍
Problem solved for that specific box.