Dynamic Subscription not Available for Paginated Reports

You need a premium capacity to do dynamic subscriptions as noted in the Prerequisites section of the docs Create a dynamic subscription for a paginated report (Preview) - Power BI | Microsoft Learn Premium Per User does not support this.

Dynamic subsciptions are available for both paginated and Power BI reports:

Create a dynamic subscription for a Power BI report - Power BI | Microsoft Learn

Create a dynamic subscription for a paginated report - Power BI | Microsoft Learn

There is no conversion tool between paginated and Power BI reports the two technologies are very different in approaches and you have to manually re-build the report if you want to do a conversion.