Neither does Worf, apparently! Yeah, I don't like that idea. But as far as I'm concerned, there's no reason to think Deanna and Data are back in Starfleet. Personally, I prefer to think Data is living on Coppelius with Soji and the other androids, and that Deanna is living on a major cosmopolitan planet -- Deneva, maybe -- where Kestra is going to uni. I mean, Seven has nearly died (often at the hands of the Borg) many, many times aboard Starfleet vessels, too. That's not meaningfully different. Or maybe co-showrunning with one of them.