Colin (Zod maintainer) and Guilo (@effect/schema maintainer) are friendly with each other, so I don't think there is any big competition going on there.

If you're a fan of the effect ecosystem, I'd probably go all-in on @effect/schema.

@e/s also has some interesting affordances, like codecs, that are not part of Zod's own design space, and could be a good fit for your specific issue where you might not always be parsing from unknown but trying to convert between different known types