The only thing you're really missing is some pulses/beans/legumes, and some more veg.

Buy yourself some more grains (jumbo oats go well as a porridge, they go well in soups, and you can use them to make flapjack (250g oat, 125 butter, 125 sugar, 3 table spoon of golden syrup, mix flatten in a tray bake at 200c for 15-30 mins, or in a covered pan on the hob), energy dense and can have other stuff added (dried fruit, ginger, choc chips, etc))

You could also add pasta and rice as two other carbs that effectively cost next to nothing, lentils and beans can give you the protein that you need, alongside the eggs

And buy an A-Z multivitamin+mineral if you don't have them already, if you're malnourished you won't be feeling great to begin with.

Keep tins of tomatoes and beans around for when you do feel adventurous

Try lentils and Dahl if beans don't agree with you

Find a local Asian/Indian supermarket and stock up on essential spices: ginger, cumin, pepper, paprika, chilli flakes. This is how the rest of the world doesn't become bored living on potatoes/rice and lentils

I am the same as you, I eat 1 meal in the evening and don't have an appetite for the rest of the day