@turkishdeelitee If your daughter is mainly eating quite salty foods that may be making her quite thirsty, and she may then be filling up on drinks / liquids (which is blunting her appetite later on for other solids). It may be helpful for you to keep track of exactly (solids and liquids) what is passing her lips each day (and over the course of a week) to see.
The milk she has after dinner, is that a large amount, is it full fat? Does she have milk overnight? Or first thing in the morning? Do you still breast feed? Might be worth working out exactly how much calorific content she is getting from milk or other drinks. (Eg does she have juice or smoothies at all, as that can be quite energy dense).
Can you try using incentives - like a sticker chart? Can you try introducing her (in a basic / age appropriate way) to food groups, and maybe make a laminated chart (of a plate) that she can stick on the different food groups when she has them, either during a day or during a meal? Other approaches include trying not to worry about the composition of different meals, but to keep track of what they are eating over the day or the week, to see if it balances out and they are getting enough energy.
Part of it may be about control - the eating of ham and insisting on more, but re du sing to eat other things. I have been in this situation before with dc - we have definitely tried to ‘gamify’ it a bit, so the get a small portion of their desired food, alongside some very small portions of maybe a couple of other types of food, and they can ‘earn’ some more of the favourite one by eating (or even just trying, one or maybe two - or three) the other things.
One thing I tried was keeping a visual chart of foods / meals that were liked - so if my dc was eating a meal or type of food that they liked, then I would take a photo of them sitting with the plate and smiling and showing a thumbs up, so if at a later date they say they don’t like it, you can show them the visual chart with all the photos of them doing thumbs up for all the food types.
Can you dress up mealtimes a bit and make them more fun, and get her to join in? Could you use finger foods to make a face on a plate, and she could choose what to put on there?
A final thought - if you daughter seems most keen on salty foods, (crisps and ham), can you try and find other foods that might give her a ‘salty’ hit - might she like small squares of toast and marmite? Or other things that are naturally salty? Maybe make popcorn with her (that is very exciting to watch, the corn popping in the pan!), then you could add a very controlled pinch of salt to it (much healthier than crisps).
Or try different type of crisps (like hand-cooked veg crisps), so that you can say to her - ‘ooh, this one is sweet potato, do you like that?’ And then get her to try sweet potato in some different ways (not just as crisps). And reward her (sticker chart or something else) when she does try new foods.