I think you need to show her some tough food love.
Assuming she doesn't have a health issue (this is important!) I'd pick a healthy food you like for her, offer it for 15 minutes or so, and pick it up at the end of 15 minutes. She gets offered the same food, out of the same bowl, the same way at dinner. If she still doesn't eat, repeat at breakfast. Then the next day's dinner. Most won't go longer than a day or two.
Our multi-dog household takes it one step further; if a dog leaves their bowl, there's no coming back to it. I'll pick it up before someone else eats food they shouldn't. No 15 minutes here - if a dog sniffs and walks, they don't eat. I don't have time to coax and babysit unattended food bowls for a quarter of an hour.
We don't have any picky/slow eaters.
Note that if you feed canned or raw, make sure it is still fresh enough each time you put the food down. Don't expect her to eat crusted over old food. Though, ours like crusted over food LOL
Also note that if for any reason you suspect she has a health problem, take her to a vet.
You said it yourself - you're down on the floor offering her a fork like an eejit. Bet she loves that!