Picky Puppy

we brought home our girl at 8 weeks, and she’s now 16 week old. She’s been a pretty finicky eater ever since we brought her home. We’ve tried switching her food shortly after and she seemed to love it for the first bit, then barely ate any. So we tried a lamb based kibble which she seemed to love, then didn’t. So we’ve tried experimenting with wet food toppers which she was licking the bowl clean of. Now she’s starting to protest that – I’m apprehensive on trying to switch up the wet food topper proteins again as I don’t want to reinforce the pickiness. We’ve also tried the 15minute tactic at her scheduled feedings. She’s leaner than what her target weight is so we really want to make sure we’re able to get her to eat her food and gain the calories she needs for growing! Any tips or help is greatly appreciated.