our current SSRS setup has Shared Datasources (to SQL server/db) so many reports can use them.
Is such a setup possible in PowerBI?
So A developer can login/use this shared datasource to build their report/db, then publish on the server, and when user executes the report, it uses a service account on that shared datasource?
You can produce a dataset in PowerQuery and optionally build out visuals. Once deployed to PowerBI Service you can connect to the dataset from many other PowerBI reports (PBIX files). You also have the option of re-using PowerBI data flows.
Control access using Manage Permissions