AshPostgres is the PostgreSQL data layer for Ash Framework. It's the most fully-featured Ash data layer and should be your default choice unless you have specific requirements for another data layer. Any PostgreSQL version higher than 13 is fully supported.
Remember that using AshPostgres provides a full-featured PostgreSQL data layer for your Ash application, giving you both the structure and declarative approach of Ash along with the power and flexibility of PostgreSQL.