ShavezAli - The decision of a single versus multiple PPGs becomes a matter of your operational preference if the underlying infrastructure that PPG is pinned to is common. In situations where you are pinned to multiple ANF storage and compute units across different data centers, then yes, multiple PPGs would be more relevant. You can use a single PPG and associate Availability Sets containing various landscapes and instances to this PPG and tie the PPG to ANF if there happens to be a single NetApp storage in that region.
I imagine for your refreshes, you are doing file level copy of the snapshot and then restoring it. As long as it meets your RTO that is fine. Having a single account would give you the option to use restore to a new volume that you can then simply attach to the to-be-refreshed environment.
Thanks for the great feedback, feel free to revert if you have questions.