Update to 21H1 vanished from WU

itsme1 said:

I haven't had anything broken with this sript, I have used it several times.

Thank you, that is valuable info.

bru said:

Don't assume WU is "broken". I was offered 21H1 on all but two of my computers. Used the enablement package but had a problem with one computer later so sys restore put it back on 20H2 and again no 21H1 is being offered.

Yes, seems i was wrong blaming WU. If I didn't have the update for almost a month and then it was replaced by "preview" CU, then I wouldn't suspect something is wrong with my WU.

jumanji said:

On my wife's HP Laptop ( Windows 10 Home 64bit) Feature update to Windows 10 version 21H1 has n't appeared in Windows Update. Yesterday I ran Windows update and only the following updates were installed.
2021-7 Cumulative update for Windows 10 version 20H2 for x64 based systems Kb 50044237 and
Windows Malicious Software Removal Tool x64 v5.91 KB 890830

Feature update 21H1 nowhere in sight. It is still in version 20H2.( Build 19042.1110). I do not want to do any forced install of 21H1. If it ain't broke don't fix it .

Wise words. And thanks for sharing your experience, my machine downloaded the same updates you mentioned.
This issue was frustrating for me as I had 21H1 offered, then waited 2 weeks till all eventual problems got resolved and then decided to install it in a way "will do it tomorrow, will do it tomorrow, will do it next weekend", until it vanished. As it didn't came back it really started to bother me.

Anyway, it seems I sort of solved the problem. I didn't use enablement package or upgrade assistant but WU.
First, I found the following Group Policy and enabled it:
Windows Update -> Windows Update for Business -> Disable safeguards for Feature Updates
Then I tried to update several times but nothing happened. So I went further, entered "21H1" and enabled:
Select the target Feature Update version
This has already been mentioned earlier in this thread by@Paul Black.
But this time after checking for updates it took much longer and WU started downloading 21H1. Except It didn't show it as an optional, but straight downloaded it, as shown:

I restarted, and am now on 21H1. Which Policy did the trick, or maybe it was a combination of both, I really don't know. Now I hope there won't be problems with 21H1 after so much trouble.

Thanks everyone who participated in my problem!

I have marked this as solved although the issue never got proper (re)solution.

Today I noticed one computer had not been updated to 21H1 and it did have the prompt to do so. Miraculously it worked. Along with all the other monthly updates on my six computers, after some trouble of course.