In MuleSoft, How to convert excel(mime: application/xlsx) data into byte[] format

In my case, I’m updating a field name that contains NAME or Number then i’m updating that field value as “******”. for example, {"firstName": "John"} is updated as {"firstName": "******"} using below dataweave code that I tried in below:

Having some trouble splitting a payload up. I basically need to split the payload every time we come across the {“type”: “AA”} object.

I need to merge two arrays of objects based on a common field, keeping the objects that are present in both arrays and combining their fields.