Take advantage of migrations in EF Core to manage database schema changes over time and keep them in sync with the data models of your ASP.NET Core applications.

Schema agnostic is exactly the opposite. You do not define the data structure upfront. A schema agnostic database system can take data, and no matter what the schema is, as long as it's well formed ...

Quite a good idea for big data. In relational databases you define your schema BEFORE you add your data. So a database with name, address, phone number etc. has those core defined schemas shapes.