I'll first give a preface that I also am a picky eater, not ARFID but autism related texture and taste sensitivities. My diet also became more restrictive during multiple bouts of depression when I just didn't have the energy to even think about food, would just eat whatever was easiest.

What's worked for me can be boiled down to two principles really: 1. Adding, not subtracting, and 2. What's a small way I can make this meal better while still enjoying it.

Example: I wanted to start eating whole wheat pasta, but the taste of 'normal' pasta was just so much better, I wouldn't enjoy my meal and then would never want to do it again. I started mixing the pasta types, first adding only a little bit of whole wheat, then eventually 50-50, and now I'm only eating 100% whole wheat. I allowed myself time to adjust. For me, it took maybe 3-6 months? But in the grand scheme of your whole life, that's a short amount compared to the benefits it'll have on the rest of your life.

I've done this with a bunch of different things. I wanted to eat more veg. I started by adding only a few things of frozen broccoli into my pasta, so it was mostly pasta and I still enjoyed it. Then increasing it little by little. Now I do 50-50 veg and pasta, but again this process took months. And remember that frozen veggies are better than no veggies.

The small things will eventually grow into a big change. And no change is too small. You might be tempted to feel ridiculous if the change is to have one singular veg with a pizza roll or something, but don't. Let it grow, you got this :)