Late to the party here, but in case you're still looking for a solution for event-persistence: @ocoda/event-sourcing is a NestJS module that offers the basic functionality that @nestjs/cqrs provides, but also adds the necessary tools for storing and retrieving events (and snapshots). On the other hand, what it still lacks are Saga's and a built-in way of doing event-replays.

Full disclosure: I'm the creator of the library.