PostgreSQL Extended Query Protocol won't cause the round trip issue; you can even send multiple parametrized queries back-to-back without any RTT penalties. This requires consideration in the API, though, because errors are delayed until the end of such a sequence, loosing attribution as to which individual query caused the error (at least at a low-level protocol level).

Not that this is a problem for a well-designed library, of course. E.g. tokio-postgres in Rust does it if you use a promise-combinator for the first poll of multiple queries inside the same transaction.