having untreated ADHD sometimes really is like, sit in front of the task that needs to be done and do nothing, get distracted by literally anything, but also not doing anything really fun because you're not supposed to be distracted.

Give up, play a game for a really short time interrupting yourself by yelling internally no i need to work, getting up, sit in front of said work and repeat. and there is no way out on your own, it's your personal hell of inability.