Migrate SSRS Reports to Power BI Report Server

I have to servers: one with the SSRS Report Server and a second server with the Power BI Report Server. The issue is I'm trying to migrate the SSRS Reports to the Power BI Report Server instance on a third server that I plan to unify both report databases. As far as I understood based on a Microsoft article (**Migrate a report server installation **), it's possible to migrate the SSRS database to the Power BI Report Server as shown in the picture to the same instance and service (Power BI Report Server in this case): I've created the backup of the SSRS databases (and encryption key) and restored on the PBI server, but it's not working. If I restore only the PBI database (and its encryption key) it works fine on the destination server. On the Report Server Configuration Manager I can only set the ReportServerPBI (that I restored from the server that already runs the PBI) to have it working. If I set the ReportServer database that I've had made the backup it doesn't work. Am I mistaken or is there any way that I can put these services in the same server/database and running under the Power BI Report Server? Will I have to keep separate instances to have both dashboard types running?