I’m no rocket scientist but that sounds like a way to create the least efficient one ever

100% Efficiency isn’t always the pure aim of rocket engines. As an example, ion engines are the, hands down, most efficient method of powered space propulsion we have in use today. However it would take millions or billions of years for an ion engine to reach near the speed of light. Truthfully it never could because you couldn’t carry enough xenon or krypton because of how many years it would take.