Spinning up a temporary e.g. postmaster instance for a test off a pre-built data directory (bonus: use zfs or btrfs or similar snapshots to make this even faster) is, IME, while still effectively "completely recreate" also both much more robust than wrap-in-transaction and generally not the slowest thing about your tests (and of course allows reliable parallelisation).

Bit of setup effort but well worth it IME even in situations where your tooling isn't strongly pushing you towards the approach.