I meant to ask, how many children do you have and what are their ages? Their tastes are going to change pretty regularly, and sometimes they will tell you they don't like something but then two days later they do. That usually means, "I am not in the mood," LOL. Just go with the flow somewhat, but definitely don't cater to whims too often! You do have to pick and choose your battles or you will become exhausted.
If you are concerned about calories from frying, have you thought about getting an air fryer? I love my air fryer. Just don't make the mistake of getting one that's too small or you will end up buying a bigger one. It's so easy, you just spritz some oil on the outside of the food item and air fry it, comes out crisp and delicious.
Also, if they like spaghetti and will eat that regularly, you can make sauce (I make mine in the crockpot) in large amounts and then freeze it into batches. Just because they are eating it doesn't mean you have to, but if it's one less thing for you to cook, you can focus more on yourself. And also that might make them curious about what you are eating and they might want to try a bite...and they might like it!
With the lasagna, did you try telling them it's just spaghetti with a different kind of noodle and some extra cheese? Are you making it from scratch or buying store premade? My kids liked Stouffer's or similar just fine, so after making it a few times and getting a "there's too much cheese" or similar complaint, I quit making it for a long time, until they were in their late teens and could appreciate it more. Throwing a frozen lasagna in the oven and making some garlic bread and salad is so much easier.