If I’m not mistaken, it’s illegal in the US to place advertisements alongside content without distinguishing them. I don’t see a marker in the screenshot; is this simply a problem with the beta?
The article calls them ads, but in the linked blog post by Microsoft only calls them "recommended apps". There's a difference between the two, and the latter doesn't have to be marked as sponsored if Microsoft is coming up with the recommendation themselves.
Microsoft starts testing ads in the Windows 11 Start menu | Hacker News