Good on you Disco, your efforts are heroic!

I think with support you could gradually wean off the formula.

Gradually is the way to go.

What would you think about hiring a Lactation Consultant?

Have you had a chat to an ABA consultant?

Also on facebook there is a group called Human Milk for Human Babies if you would like to source donor EBM in place of formula (which I did during my low supply struggles.)

I think with good support, and some good galactogogues, and looking after you too with enough rest and good food, there is a really good chance you will be able to gradually cut down on the formula and maintain a plentiful supply - sufficient for your baby.