I'd add on to what Josh is saying: it is extremely unlikely we'd switch the standard FusionAuth Cloud hosting service to CockroachDB. PostgreSQL meets our needs very well at this time.
However, it seems like CockroachDB compatibility is very close. I think there was just an issue with social logins and I believe that the FusionAuth user interviewed in the linked blog post filed an issue with them, as you mention.
Given that information:
feel free to host FusionAuth with CockroachDB in your own environment
if you are interested in FusionAuth building out a special deployment for you with CockroachDB,
you can contact our sales team. This type of custom work typically requires an
enterprise contract.