It could work in theory, since it's supposed to be compatible with Postgres, but last time I checked they don't test against it, and it's not anywhere close to 100% identical (https://www.cockroachlabs.com/docs/v22.1/postgresql-compatib...), so I'm personally not too comfortable relying on it for production workloads.

Things might have changed since though, I'd try asking folks in the forums to hear their experiences with it before diving in. Would be awesome if this setup worked well though!

I personally prefer Fauna from an operational perspective since it's a 0-maintenance SaaS that scales pricing with usage with a generous free tier, but it's probably unlikely to be supported anytime soon.