A new and streamlined Report Builder was released on October 16, 2024. It is supported on Mac, Windows, and web browsers.
This Legacy Report Builder add-in version still works. You can convert your legacy workbooks to the new Report Builder.
Once you create a request, that request will always have the same reference in Power BI. But if you delete a request, the reference will be used by a new request you create for the same dimension.
If you delete a request in your workbook, make sure that you do not have a visualization pointing to that request in Power BI, because otherwise the visualization will break.