You can actually walk in and enquire with MBPJ and they can provide you a list of panel draughtsman there; to expedite your approval. You can work with this draughstman to get your approval done. Due to Covid-19, it might be best to call first before going there.

My own renovation approvals were less than RM 5k including the draughtsman fees but I lost his contact, done 6 years ago and mine is conversion from 1 storey to 1.5 storey