Maintainability of schema changes during runtime of an app
If the data is going to have many different layouts, you might be overthinking it.

Many DBMSs have great support for JSON now. You can store it natively as JSON while defining a view on top of JSON data that exposes it to other users as a regular view with columns.

https://www.postgresql.org/docs/current/static/datatype-json.html

https://docs.microsoft.com/en-us/sql/relational-databases/json/json-data-sql-server