Your neurodiverse or ADHD employee may be highly motivated if you give them a problem and ask them to brainstorm the solution with you. Not only will you get outside-the-box solutions but your employee might be so energized with the solution they work twice and hard to get it done.
You need to fall down periodically to learn to walk. Work is the same way. If you want great results, allow your employees to try new things. They will occasionally fail but the successes will most likely far outweigh the failures over time. Plus, you earn dedication credit from your employees for accepting that they are not perfect.
When your neurodiverse employee is on a roll, they don't want to stop. This is called hyper-focus. Unfortunately, hyper-focus can also result in your employee working way over the 5pm closing time. But, do you allow them to come in late the next day? Talk to your worker about the rules, where they can bend and where they cannot bend. Work together to determine how to handle time clock challenges that might derail either productivity or perception of dedication.