Hi, @Roberto
Thank you for posting in Microsoft Q&A forum.
In the wizard I choose Product "Windows 10, version 1903 and later" OR "Windows 10, version 1903 and later" (Yes, I see two of them)
This is a known issue of SCCM, for the details, you may refer this article.
And you only get "Update Rollups", please check the classifications in the SUP component properties, whether you have checked other classification. If not, please check the classifications you need, then wait for one minute and then do a synchronize.
To configure the SUP component properties, navigate to Administrator\Site Configuration\Sites\right click the site and select Configure Site Components > Software Update Point.
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