Batch operation does have
PartialUpdateObject BatchAction = "partialUpdateObject"
PartialUpdateObjectNoCreate BatchAction = "partialUpdateObjectNoCreate"
but there is no documentation how to use partial update object operation (Partial Update Objects API Reference | Algolia) with batch operation.
The plural version (PartialUpdateObjects) should support batching the same way SaveObjects does. Just pass your object list into the method.
As mentioned on that page, you do need to be aware of rate limiting on the API, just like other operations.
I want to use custom batch method not partial update objects method though