Don't just start with a relational database, but keep using it. There's very few use-cases for NoSQL document-oriented databases and this one is definitely not

Don't just start with a relational database, but keep using it. There's very few use-cases for NoSQL document-oriented databases and this one is definitely not it (at least not as a primary datastore - you may use those for search in addition to your primary which will be the source of truth).