Core component of SQL Server for storing, processing, and securing data
As long as everything is running on the same server, the easy solution is to add TrustServerCertificate=yes to the connection string in the PowerBI Desktop.
This setting is not suitable for network connections, as it opens for a man-in-the-middle attack. That is, someone may install an evil service between PowerBI and SQL Server that pretends to be SQL Server. This service can steal or manipulate data. But that is a little difficult to do on a local connection.
For network connections, the recommended solution is to install a proper certificate. I believe you buy this from a trusted Certificate Authority. As I work in a developer role, it is something I have never done myself, so I am foggy on the details.