Hi @StefanoGrimaldi ,
If your sql sever database is deployed locally, then you do not need to give your user access to the sql sever database, because the connector created using the gateway is implicitly shared connection. An implicitly shared connection means that the user implicitly uses the credentials of the account that the app maker used to connect and authenticate to the data source during while creating the app. The end user's credentials are not used to authenticate.
Since both the app and its connections are deployed to end users, it means that end users can author new applications based on those connections.
If your sql server database is deployed in Azure, then you need to give your user sql sever database access, because this connector is an explicitly shared connection.
I think this link will help you a lot:
Use Microsoft SQL Server securely with Power Apps
Best Regards,
Bof
