WSUS error during feature update to Windows 10 V190x

[German]Administrators who use WSUS to deploy a feature update to Windows 10 V190x reports that this fails with error codes such as 0x80070057 or 0xc1900298. There are now two different cases that have come to my attention or have been reported by readers.

WSUS throws error 0xc1900298

In this comment within my German blog, reader Ralf Münz reported that he run into serious issues deploying feature updates in WSUS. Ralf wrote (I've translated his German comment):

Hello,
I also have here the problem that an update from 1809 to 1909 appears with an error 0xc1900298 in WSUS With manual search the download is repeated after the error and 1909 is installed, but automatically in the background not. Has anyone observed this and possibly a solution?

A search brought me to this article, referring to a post in the Norton Community. Mostly it is assumed that it has to do with installed third party antivirus products. These sometimes lead to damaged update databases on the client. 

WSUS throws error 0x80070057

Another case was reported by blog reader Stefan T. via e-mail. I will post the facts of the case here on the blog. Here is his observation (I've translated his German message).

maybe you have come across the problem in your own or in your blog that the WSUS (don't know if it only affects server 2019) doesn't distribute the function update to e.g. 1903 or 1909 and instead gives error 0x80070057. Below in the links (there are more) are also fellow sufferers who have exactly the same problem. "Normal" updates work without problems!

Regarding the update error 0x80070057 I had compiled something what can cause this error code in the blog post Windows 10: Update error 0x80070057.

More admins affected

In German ComputerBase forum there is this post where the update error 0x80070057 is discussed in connection with WSUS. And at German site administrator.de you can find a thread that also deals with the error. There it says that the installation via ISO installation file is working.

No solution so far

Stefan writes Unfortunately nobody seems to have a solution yet… …and claims to have already tried many things. Among them:

WSUS newly installed on VM with Server 2019
Adjustment in IIS (settings memory / protocol etc.)
MIME type changed – one has also written delete entry completely?

Tried different registry settings according to the forums

Such an .ini with entry "DynamicUpdate=Disable" created see (if he wants to check something online before downloading from WSUS)

Stefan writes: I have tried many things, but the clients are offered the update and probably don't download it (at least the .esd file). And he added:

At first this looked like the problem I had before, that the .esd was not registered in IIS – but it is. Neither as MIME type "application/vnd.ms-cab-compressed" nor as "application/octet-stream" it works.

Somewhere you read between the lines that it wouldn't work offline, but if you do it with the ISO, it works – but that can't be the solution to go to more than 100 PCs with an ISO. The whole thing should run in the background without doing anything. You don't have that much time and the employees should be able to continue working during the installation. That's what WSUS is for.

Question: Does anyone of you have a solution for the above update errors?