Attached is an implantation of jsonb_delete that instead of taking a single key to remove accepts an array of keys (it still does just keys, so it's using the - operator, it's not like the path delete function that also takes an array, but uses a different operator).
In some simple testing of working through a real world usecases where we needed to delete 7 keys from jsonb data, it shows approximately a 9x speedup over calling the - operator multiple times. I'm guessing since we copy a lot less and don't have to re-traverse the structure.