If the data is highly relational, no JSON structure and data duplication will save you from joins. You will either do them at database level or in memory.

I see a need for relational databases, NoSQL, data lakes and all other storage strategies. You chose based on the type of data, the way you acquire it, the way you process and deliver it, based on security and reliability needs.

In many non trivial application there is more than one data storage solution implied. Since I work with large microservice based apps, it's a long time since I have to use more than one data storage strategy in the same app.