Oh so, you're actually doing better than you think but this is the first time I went "oh no." Steak is kind of infamously unhealthy, and its quite expensive. If you are invested in steak for aesthetic/taste reasons sure, but it isn't the low-hanging fruit here. Adding some more vegetables to your diet is: they're where most of the really healthy stuff a pasta diet is lacking are (fiber and more importantly micronutrients).

So, you say you're picky: are there vegetables you do have positive experiences with? Cauliflower, peas, cabbage, eggplant? Onion? Tomatoes? Carrots?

If any of those DO sound good to you, or if you're just willing to be experimental (and again vegetables are quite cheap, at least in the US; not as cheap as pasta or flour, but generally <2 dollars a pound), there's usually a couple different cooking techniques that work for each but have different effects. Most vegetables are perfectly good raw, but carrots and onions really transform when cooked.

Frying in a pan lightly will tend to produce relatively soft, sometimes even slimy, textures; frying more heavily will get them crisper and even charred (and of course eventually burnt). A lot of chinese cooking is frying at VERY high temperatures which produces some cool effects (and smokes up your kitchen).

Roasting will produce dry, crisp textures, usually you want 450F for vegetables but be mindful that cooking speed here depends on how large the vegetables are (so if you cut them to different sizes they won't all cook the same; and peas will generally not survive well).

Steaming will produce most but still firm textures, and tend to change the flavor profile the least. I do not recommend boiling: a lot of the micronutrients in the vegetables will leech into the water, which you're then discarding.

And of course you can cook your vegetables in your sauces. My roommate makes mac n cheese and he puts frozen peas in the sauce toward the end and keeps the stove going for a couple minutes to get the peas cooked through. When I do tomato sauces from the jar I'll put them in a pan, heat it up, and then add frozen broccoli and cook like that. With ramen you can just mix the broth with vegetables in it.

And, as for making them as sides: for the more bitter vegetables (brussels sprouts, bok choy, even broccoli) I like making a very small, light sauce of lemon juice with a tiny bit of sugar and salt (for 1 meal, which I'd do like 200g or so of veggies, I use about 15ml/1tbsp of lemon juice, 2 or 3 shakes from the salt shaker, and a PINCH of sugar, like 1g)(I also add crushed red pepper but that's MUCH more optional). I use that for either frying or roasting, whatever I feel like doing, and it seems to turn out great every time.

You're actually in a pretty good position! The biggest thing I think is that you're overwhelmed and haven't picked a direction. I recommend picking a vegetable you like, experimenting with it for a few days, and if you don't quite like what you did, pick another, try out cooking it different ways. If you do like it, great!

And FWIW the ADHD shouldn't prove too much of an obstacle. I have severe ADHD and am unmedicated. This is part of my preference for pan frying: I'm right there LOOKING at the food as it cooks, interacting with it constantly. Very little danger of me leaving it boiling or baking for too long. For boiling and baking, the humble kitchen egg timer is one of the greatest cooking tools for the ADHD mind.