Cannot copy big portions of certain pix folders - ownership problem??

Hello,

Not sure if my issue is related to the same W10 update on 28.08.20 mentioned in my post about SyncBack, but although it seems the issue is totally different from the one below, the start is around the same date/occasion:

It seems an unknown number of my folders has new and strange ownership/permission issues.
Example.

I backup most of my stuff on external hdd's 2 or 3 times.
Since a few days I have problems doing that.
The pictures are visible on main drive E and backup drives F & H & W, but hundreds of pictures can NOT be copied. Although they already do exist and are visible on the 3 backup drives. Syncing vice versa (after having deleted the synced main part of the collection on E) did not help either. From E to F many existing files can not be copied, from F to E the problem is the same.

Googling brought me to the ownership/permissions section of Windows (which I hardly understand, no experience).
But following the recommended steps brought no solution: all permissions are mine - I am the only user of my PC.

And doing chkdsk repairs and Paragon system file checks did not make any changes - after several hours of patient waitings...

What is the cause of the trouble?
And what is the remedy?

Thanks!
Wim

Winver 64bit
Version 2004 OS build 19041.450

A big folder with my home & holiday pix.
I am the only user of this pc, always run it as administrator.
For Syncback itself there IS no specific administrator option.

Error messages like:

date/time
folder/filename.jpg
Error: Failed to copy from source - Cannot copy file (1392) - The file or directory is corrupted or unreadable

It takes around 10 seconds to check a file. Then this message pops up in the error list.
The first around 1000 pix were normal.
And...
If I click on each of these files, they show themselves normally.
But if I make a single copy to a destination where it already IS (!), I see a message that this file already exists, should I overwrite it?
And then I see one pic normal, one with green/yellow error stripes...

No idea....

I am doing experiments with copying single files. Disturbing, confusing, strange results so far. Examples:
- I have a folder E:/pix with around 500 files, many seem corrupt (cannot be copied) but can be displayed without a problem or delay
- Copying the whole folder to F:/pix fails for more than half of them
- Doing it one by one gives these results:
a. Copying is possible, but pasting does not show anything in F
b. The picture is copied to F but the copy cannot be opened
c. The picture is copied to F but can only be opened after a long delay
d. Trying to open the picture in F makes the whole Windows Explorer and sometimes the whole pc freeze/hang
e. The copy in F can be opened but is apparently corrupted with green/yellow/purple stripes for part or whole of the pc.

Tools like chckdsk can scan/repair disks - are there also tools to scan/repair individual files/pix?
A friend suggested that a recent copy by TeraCopy could have corrupted many files. What is your experience or idea?

Greetz,
Wim