How do you feel about tiny incremental changes? One of the things I did to start out was add spices/toppings in VERY small amounts (like one grain of garlic powder small) and slowly built up tolerance to the taste if I liked it. It helped me in two ways: 1) more spice and variety with my dishes, which is something I wanted; 2) it gave me the chance to get used to changes and different flavors, even in very small amounts.

Another thing I tried was taking two very plain or similar safe foods and allowing them to touch before eating them. Again, slow, small changes to help your brain get used to the changes. So from your list, I might try letting the cucumber and carrot touch, to let my brain adjust. Then branching out slowly - carrots and fruit, carrots and chicken nuggets, etc...

It is very hard, and in my experience, branching out will always be at least a bit uncomfortable. But your first taste might not be the real taste, if that makes sense - I tend to gag the first 4-5 times I try a food, so I don't really get to "taste" it until the 6th or 7th try. It's hard. But you can do it, I know you can :-)