5 years ago I could have written this post. Except occasionally I did get a spoonful into DD's mouth, at which point she'd vomit to get it out. I cleaned up an awful lot of vomit.
The good news: DD no longer consumes only milk. The bad news: she eats a pretty restricted diet, and it's taken a long time to get there. I think she only switched to getting the majority of her calories from food rather than milk when she was 3.5 (years old).
We did see dietitians - only managed to get an appointment when she was 15 months, when they suggested trying anything (including chocolate!). They also suggested restricting her milk to make her hungry, which I refused to do - when she went to nursery (at 3) she refused to eat or drink anything in the 4 hours she was there for over 6 months, before finally deciding she'd try the stuff she was already eating at home by that point.
I don't know what formula your DD is on, but we were strongly advised to switch to 6+ stuff, as it has more iron in it, which children of that age need.
What helped me was choosing to be less stressed about it - DD was never underweight, and managed to drink so much she was overweight at 3.5, so she was at least getting enough to eat. I think we just kept presenting her with food - the first time she chose to eat, it was pizza, and we hadn't given her any, but she grabbed some from someone else. I'm afraid I can't remember how old she was! For DD now, the main issue is texture (and I think it always has been) so you may be more likely to have success with something lump free. DD also preferred very dry food, e.g. crackers, cheerios.
Hope that helps. Feel free to ask me more questions!