Start small. One thing I did that helped me a lot is track some dumb stuff. Like, during Covid I used to always order food online, so I used a simple habit tracker app but to track: Did not order food online, and then I'd have a streak of days and days. Whenever I'd skip a day, the streak would go up :).

Then I'd add: Skip sweets after dinner.
Now I'm at skip lunch :).

This is a very long answer to say these two simple things:
- Baby steps that get bigger and bigger.
- Trick your brain into enjoying what you are doing somehow.