CockroachDB uses the same PostgreSQL wire protocol and SQL dialect so it just looks and works like a pg database. There are some minor differences but DDL and data types are already included in the syntax: https://www.cockroachlabs.com/docs/stable/porting-postgres.h...

It's great if you want to contribute though but I'd recommend just working on the PG EF Core provider which already has some work towards CRDB specific features: https://github.com/npgsql/Npgsql.EntityFrameworkCore.Postgre...