tinanam0102“Would "bit by bit" also fit in this content?”
Sorry, I didn't realise that was part of the question.
It doesn't seem a good choice here. "bit by bit" is usually used for finely divisible things (for example, "add the flour to the mixture bit by bit", "bit by bit, I began to gain on him") rather than discrete items. It's also rather informal and chatty, and not very appropriate for a business communication (as this seems to be).