In MD
In MD Mopeds require insurance. I do not think the insurance is that much - about $100 annually for me. One time registration. However in MD E bikes are bicycles, not motor vehicles, and e bike classes 1-3 are allowed on most roads. No insurance or registration for e bikes in my County.Can't you just register it as a moped? Costs a whole $9. 25 mph speed limit. No insurance required.
Most states have moped laws that can be used for ebikes, and are often more permissive, provided you pay $10 or $20 and stick some tin on the back. Class 3 Laws seem mostly just a way for the US bike industry to sell motor vehicles to people without a drivers license, which seems short sighted...