Azure Policy Assignment Query

Team,

        We have 100+ Subscriptions in our infra under single AD.

        We have created a Azure Policy to refrain user to create High end Virtual Machines which is tested fine.

        We don't have any Management Group created at the Moment and Now we have to assign the Policy to all 100+ Subscriptions.

       Since the scope is restricted only to my Test Subscription, we couldn't Apply the policy to other Subscriptions using PowerShell, only way I can make it work was duplicate the policy and scope to new subscription and its working.

       Is there any other way than Management Group which is planned for later. Kindly help.