6 brutal hours working with three different MS techs on a paid incident and the update problem solved. In my case it was a driver, maybe for my NVe ssd drive, that update couldn't find. A manual update was also done but probably not needed.  Installing that was not trivial.

There are update logs that have to be searched for errors.

Thank you for your time on call today. Please see below the troubleshooting steps used to resolve the issue -

 From Setupapi.dev.log  -

[Boot Session: 2021/04/28 18:35:16.500]
 
>>>  [Install Driver Updates]
>>>  Section start 2021/04/28 18:35:28.411
      cmd: C:\WINDOWS\winsxs\amd64_microsoft-windows-servicingstack_31bf3856ad364e35_10.0.19041.963_none_e7400f2b262ca554\TiWorker.exe -Embedding
     sto: Image State        = Specialized
     sto: Image Architecture = amd64
     sto: Image OS Version   = 10.0.19043
     sto: Image Product Type = WinNT
     sto: Transaction        = CbsDriversAndPrimitives
     sto: Driver Updates     = 655
!    inf: Unable to load INF: 'C:\WINDOWS\System32\DriverStore\FileRepository\nvraid.inf_amd64_144351277838b429\nvraid.inf'(00000003)
!    inf: Error 3: The system cannot find the path specified.
!!!  inf: Invalid INF 'C:\WINDOWS\System32\DriverStore\FileRepository\nvraid.inf_amd64_144351277838b429\nvraid.inf', parsing error on line 0. Code = 1002
!!!  sto: Failed to get version info for driver update 'C:\WINDOWS\System32\DriverStore\FileRepository\nvraid.inf_amd64_144351277838b429\nvraid.inf'. Error = 0x00000003
<<<  Section end 2021/04/28 18:35:29.600
<<<  [Exit status: FAILURE(0x00000003)]

The Driver file was not present at the location -

The registry was also missing for nvraid.inf

Steps performed to mitigate the issue:  

 
As we see issue is caused by nvraid.inf, we omitted the driver operation upon reboot by deleting its entry under below registry path:
 
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\DriverOperations
 
Note: You need take the permission of the registry key and locate the entries for driver ntprint, delete them before restart.

Post removing the nvraid.inf registry entry update got installed successfully.

on windows 21h1 already solved the black screen error with the mouse arrow ??

@farhadabdul, 

21H1 is now at build 19043.964, I don't have any problem with it.

If you are still at 19063.899 did you try to update to the latest level ?

on windows 21h1 already solved the black screen error with the mouse arrow ??

You are showing you are on build 19041. This update (962) was released to Insiders for 19042 and 19043. 

Ok, thanks for pointing this out. Somehow missed this :-|
Will look for info/solution elsewhere then.

FY: Correct: I am on Version 2004 - OS Build 19041.899 (Insider Beta Channel)
Have been running Insider Beta Channel for a long time on this hardware without any problem.
Starting on ‎2021-‎04-‎14, Feature update to Windows 10, version 21H1 showed up starting to giving error  0x800F0984 (on every retry...)

Tried disk-cleaning up Widows update, tried resetting Windows Update, problem persists.
Reported this problem in detail on Feedback. Expecting WU to fix this though the beta channel, preferably without me interfering?

@Theo van Elsberg, 

If you are on Beta how can you still be on Version 2004 ? The current Beta channel is on 21H1 not 2004.

Use the insider ISO for 19043.867 and upgrade your system using the setup from the ISO file.

That works and bypasses the error error  0x800F0984, it will bring you system to 21H1, if you do that while online it would bring you to 19043.962.

You are showing you are on build 19041. This update (962) was released to Insiders for 19042 and 19043. 

Ok, thanks for pointing this out. Somehow missed this :-|
Will look for info/solution elsewhere then.

FY: Correct: I am on Version 2004 - OS Build 19041.899 (Insider Beta Channel)
Have been running Insider Beta Channel for a long time on this hardware without any problem.
Starting on ‎2021-‎04-‎14, Feature update to Windows 10, version 21H1 showed up starting to giving error  0x800F0984 (on every retry...)

Tried disk-cleaning up Widows update, tried resetting Windows Update, problem persists.
Reported this problem in detail on Feedback. Expecting WU to fix this though the beta channel, preferably without me interfering?