my gal last time also latch on for fun as she grew older. I've stop bf. You need to really be persistent not soften & let her latch on when she cries. Tots are clever to know how to manipulate mum.
You may try to say mummy no more milk
Let daddy feed her formula & you disappear. dont't show yourself as daddy is preparing FM or feeding her. Seriously dont't even show yourself otherwise thought will stop feed. Daddy can say you're out or working
Teach her during non-feed time that she needs to drink her formula
You need to gradually feed her formula not at once. Since you're stay at home mum best i suggest to try night-feed so daddy can feed her FM, as you drop a feed for bf. Whichever timing is best to start with daddy.
Just some experience to share good luck