My macaw took until he was 2 years old to wean.
He was mainly on a once daily comfort feeding after the first year or so, but still he requested it so he got it. He came to me abused though, and it benefits their mental development greatly knowing if they need that comfort feeding, it’s there.
Circumstances of the babies life before you, individual personality, and any illnesses that may happen all can play a part in extending or shortening the time your little one will need to be hand fed.
I’m glad you’ve got a vet appt coming up to be safe and I agree with the others who said it’s possible that the dip in appetite could be from the desire to be a bit more mobile.