Many people with ADHD find the Pomodoro Technique genuinely helpful. A visible, ticking countdown externalises time, which is powerful if time tends to feel abstract or slippery to you. It also breaks an overwhelming task into a small, concrete piece you can actually start.
You will probably want to tune it. Some people need shorter sprints (10 to 15 minutes) to get going, others hyperfocus and want to keep the timer from interrupting a good streak. Treat the 25 minutes as a starting point and adjust until it fits how your attention actually works.
This is general information, not medical advice.