As someone with 7-year old, ADHD-I and AuDHD-C twins, I just have this to say: If you figure it out, please let me know!
I heard about a service that might help: https://www.focusmate.com/
I haven’t used it, but I’ve thought hard about doing so.
There may be a difference between habits and muscle memory. Seatbelts and parking brakes would be the latter.
As someone with 7-year old, ADHD-I and AuDHD-C twins, I just have this to say: If you figure it out, please let me know!