Mine almost never eats supper, unless it’s pizza. Every other supper he’ll eat two bites of. I do think toddlers go through that stage. We just try to balance it, give him foods he likes for breakfast and lunch so that he’ll eat something, and then at supper he’s exposed to other foods so he can at least try them.
My LG is the same sometimes. Sounds like a toddler issue where they’re figuring out what they can get away with. I don’t think you’re doing anything wrong, maybe you just need to add some options to your situation. For instance, my go to option to use is cartoon bribery. Like “if you eat all your breakfast, I’ll let you watch a SpongeBob after”. Or maybe try to keep the same plate to eat off of. So if she doesn’t eat all her lunch than when she wants a snack she has to eat her leftovers before eating that snack. And then one attempt at encouraging any type of nutrient intake is sometimes only having healthy snacks as an option, this way if she’s not eating her meals at least she’s getting plenty of fruits and veggies for that day.
That’s how kids are they aren’t going to sit still at a meal sometimes but not every single night doesn’t matter if it’s a meal they like or not. That’s toddlers