@Kapil Arya
Thanks for your hints.
I have used Health Check many times and again now. I got always "Great news - Windows 11 is free and coming soon. ..." .
When following your link, I land on a page saying that my box is ready. Then I'm directed to the "Settings" app at "Update". Checking again for new updates brings "You're up to date!" and not any word of W11.
So I'm afraid that WUS may have become asynchronous because of the short absence of the TPM device and no longer looks for an W11 upgrade.
So my question in the post is unanswered. I'm looking for guidance whether this behavior of WUS not to announce a free upgrade coming soon is normal or does it mean, that WUS will not upgrade my box.