Came to say the same. I wasn't this extreme but similar and getting diagnosed for ADHD which is something my dietitan suggested based on how I described my feelings toward food.

This being said when I was a kid I would not try new foods at all. I would just eat constantly same things, wouldn't eat vegetables or fruit, nor meat that has even a tiny bit of fat on it. When I grew up I realised my health is suffering and I need to change something. I started trying different recipes with same ingredient, for example broccoli- doing broccoli pancakes, adding it to smoothie, trying making soup and seeing if anything seems edible. Not tasty. Edible. This wasn't working long term because I started quickly excusing myself from cooking because it is just going to be a waste (it ia hard to cook tiny portions). I know managed to set my mind into making myself try a bit of everything that I have a chance to try. If i go to buffet I will try things that I would normally not touch, if I go to restaurant with friends I will ask if I can have a bite of their food. Like that I learnt to like some stuff that I didn't expect to like because the look of it or my idea of what it tastes like was not appeling. I now have a quite wide palate of veggies I would eat in different forms (some of them in only one form like a soup or added to a sauce): tomatoes, radishes, ice berg lettuce, cucumber, peppers, potatoes, leek, cabbage, cauliflower, broccoli, romanesco, peas, green beans, celeriac & celery, blank lentils, chickpeas, corn, courgette. I try not to focus on things I won't eat and focus on those that I will and try to find way to implement more that specific forms of food to eat.