It's strange, I can find the policy objects in dashboard under help API docs, but the interactive API docs doesn't have these endpoints yet. These are handy because they contain examples and an import for Postman.
By the looks of the POST and PUT calls you can only add or modify one policy object at a time.
And for action batches, normally if the documentation would have been complete then you would have known if these calls can be put in an action batch.
For now, you'll need to script a series of these calls and just catch the error if you made too many calls and make it wait the time.