I’m unfamiliar with .NET Core and C# and am working on a project with a .NET developer who claims we should not use MySQL or Postgres because performance would suffer?

He also maintains that SQL Server does not work well if you fully encrypt the DB.

The application is pretty basic in that it will primarily be capturing text based data the will be reported on later. There are no major batch processes or mathematical calculations running.

The plan is to run the application in AWS and I suggested we look at using a DB other than SQL Server to avoid MS license costs.

Is there something inherent about .NET Core and C# that would make using MySQL, Postgres or Aurora a bad choice for a database?