Just Buy a Moped or a Vespa. their Brakes will match the motor power,
the brakes on a bicycle will be weak.

they're weak on some of the electric bikes on the floor at the shop, here, IMHO.
Needs a beefy fork for 210, 8"+ disc brake, at least.

And, if it runs on while you are not pedaling,
It becomes a Motor Vehicle, so you are now subject to the DMV in your state.