A few things need to align. The author has already explicitly stated how big a problem this is for them. That's a really good start. It sounds like the author

A few things need to align. The author has already explicitly stated how big a problem this is for them. That's a really good start. It sounds like the author is making these realizations all after the fact. The next step would be to notice what's happening right before they go into daydream mode. This is difficult and takes a lot of practice/failures. That basically works against a coping mechanism they've apparently had their entire life. So the things they are coping with come into the foreground, and doing that can be scary and extremely disruptive. Therapist recommended for this step. Finally, there's a way to look for comfy little toy problems to practice making a decision to do something other than the daydreaming. Things that are low risk and high reward. Imagine a vacation where your train departing while another goes the opposite direction, and you suddenly realize your deep desire is to tell the guy in the other train, "Hey, you're not allowed to smoke in there!" Bam-- perfect toy problem. You'll never see them again, and you can spend a bunch of time after that seeing what it felt like to say the thing that daydreaming prevented. But to get there you've got to be aware of the opportunity, and that takes time and practice.