Work under way.
You are what you eat. You just can’t get away with stuff the further on in life you get. If you eat crap, you’ll feel like it.
Having self-control in this area is brutal. That makes it a good opportunity for a win. Just don’t use the word diet.
I think that owning your food intake is what’s needed. It’s easy to look at plan you can by and maybe it works for a bit. And then you quit.
How much effort did you put into forming that pre-made diet? None. That’s why you don’t own it. Write down your plan for you. A person can use different plans as part of better eating, but view them as a supplement for your goal. It’s about you and your health.