It’s hard but it sounds like she is eating enough of a variety for now. She isn’t living off biscuits and buttered bread so I’d try to recognise the healthy things she does eat and slowly try to build on that with the pressure off.
Limiting snacks works for us. My 4 year old only gets snacks after swimming as that’s when he is truly ravenous and can demolish a packed lunch box of fruit, cheese, crackers, flapjack, yoghurt etc but still eat dinner later. Otherwise the only snacks on offer tends to be fruit, veg, humous for dipping and occasionally rice cakes or a little cheese.
My son’s diet is a rotation of the same things: tuna or pesto pasta, spaghetti bolognese, cheese sandwiches, chicken soup, pizza, scrambled eggs, porridge, fish fingers, and sausages. Additionally he eats fruit, sweetcorn, red peppers, cucumber, yogurts, homemade healthy ice lollies, and things like breadsticks or rice cakes with humous. This isn’t a huge menu but I feel it covers all the food groups and essential vitamins so I don’t worry that he refuses to join us in eating curry or salmon etc. I put new things out now and again for him and we just slowly (very slowly 🫠) work on it with no pressure on him.
Look at what your daughter does eat:
Fruit
sausages
chicken (yes it’s nuggets, but it’s still chicken)
fish cakes
pizza
fish fingers
potatoes
cucumber
carrots
peppers
various pasta dishes
This is so similar to my son and genuinely I think she’s doing great. A balanced meal could be tuna pasta with some chopped up cucumber and peppers on the side, or fish cakes with a little macaroni cheese, with a fruit salad served afterwards- absolutely nothing wrong with these dinners at all.
Some tips that work for me to bump up the nutritional value of meals:-
-Make pizza together and pre-make your own tomato sauce base. You can roast so many veggies and blitz them to make a hidden veg sauce
-Make healthy smoothies/ice lollies together with a little honey to sweeten
-Deconstruct meals. Serve bolognese as separate parts: some spaghetti, a few teaspoons of the bolognese, and some grated cheese
-Mash/blend a little avocado into green pesto. Avocado disappears so well into creamier sauces too. I mash it into tomato and mascarpone sauce for my son’s favourite tomato pasta dish.
Other than that just carry on as you are and keep the pressure off. Keep eating meals together and try to serve your own meals in separate parts as she will be more likely to want to try some of what you have if it’s all in separate dishes and not already served up on the plate. When we eat curry my son will try the rice and the poppadoms even though he might be having tuna pasta. He’s still part of the experience and gradually he’ll try more things I’m sure.