Describe the solution you'd like
I would like AWS Parameter Store provider to retrieve entries in a batch using GetParameters instead of 1 by 1 using GetParameter

What is the added value?
Usually a lot less calls to Parameter Store (1 per ExternalSecret instead of 1 per .spec.data entry) helping with scaling for large parameters sets.

Give us examples of the outcome

I would see moving this loop to a new provider.GetSecrets function

Default implementation would just call provider.GetSecret for each entry, but would allow implementing more efficient batch retrieval functions for providers supporting them.

Observations (Constraints, Context, etc):
As a context I was looking into configuring and improving performance of External Secrets for large (10k+ parameters) Parameter Stores. I stumbled upon each PS request having different userIdentity.principalid in reported CloudTrail Lake results and dig further into it. While i did not find the reason for session per each request I found a possible improvement that i described here.