I don’t have a response to your first question - some modern e-bikes are very capable. But in many jurisdictions registering a moped is extremely easy - in MA

I don’t have a response to your first question - some modern e-bikes are very capable. But in many jurisdictions registering a moped is extremely easy - in MA and VT at least, it’s honor system. In MA you have to go into the RMV but don’t have to have anything beyond the bill of sale and a VIN. VT you can even send in the form, you don’t even have to live in VT. You usually have to have a learners permit at the very least - sometimes a drivers license. I’m sure there are some places where you need a motorcycle endorsement, but I’m not aware of any in the US.