At the moment you need massive sharding options with Postgres, you've got a lot of options. I'd assume by the time you get there, you can probably budget for them pretty easily as well.

Citus is specifically designed for it.

Timescale appears to have the use case covered too.

Ultimately though, sharding is one of the easier ways to scale a database out. NoSQL just does it by eliminating joins. You can do that pretty easily with almost any solution, PG or otherwise.