How to fix a picky eater

So my dog is about 11 months old. We’ve had her for 7 months. We were feeding her Purina puppy chow when we first got her and she loved it. Then over the course of a few weeks she slowly stopped liking it. So we switched her to Purina One Puppy food. She liked it for a few days then stopped eating it. So then we switch to half canned food and half dry food of the same brand. She will sometimes eat it and sometimes not. We’ve tried different food toppers and none of them worked and I didn’t want her to think we would just give in if she doesn’t eat it so we have stayed pretty consistent with just the Purina One Puppy canned + dry food. Sometimes when I feed her, she doesn’t even go near it, other times she eats it right away, and other times she will move it around with her nose for 20 minutes before I eventually take it away. We feed her twice a day and if she doesn’t eat one of the meals she will eventually throw up bile, but that doesn’t seem to phase her. I’m about 6 weeks pregnant and we simply cannot spend this much time waiting around for her to eat and getting frustrated about her not eating and then just wait around for her to throw up bile. Does anyone have any advice!? Also, if I were to throw that whole plate of food away and then set the plate back down on the ground, she will lick the plate clean from whatever was possibly left on there. I don’t get it.