Ideally a RDBMS can also be a NoSQL DB. There is no reason it can't/shouldn't, if you have JSON-formatted columns.
Mostly the noSQL pattern is a mistake because you almost certainly have columns that recur reasonably frequently, but if you do have high-dimensional data or want to store processed documents/etc, you can represent them as a JSON/JSONB in postgres/etc, and even run indexes or queries on them.
Mostly the noSQL pattern is a mistake because you almost certainly have columns that recur reasonably frequently, but if you do have high-dimensional data or want to store processed documents/etc, you can represent them as a JSON/JSONB in postgres/etc, and even run indexes or queries on them.