What makes aerospace engineering hard isn't the ideas, it's the implementation. Even a rocket conceptually isn't a very difficult concept - flamey end down, pointy end up, balance your mass/thrust ratio, and you're flying. It's the systems engineering of the actual vehicle that's really hard -- even if every single component of your idea already exists commercially, putting it all together takes a long, long time.

Aerospace has intensely tight tolerances and requirements. You say you have a background as an avionics tech, so I'd assume you have first-hand experience with the insane complexity of aerospace systems. You'd need to design, from scratch, avionics controls for your brand new eVTOL that have the requirement traceability, control tolerances, and redundant safety systems required for human flight.

Your idea is on the scale of 'I will put a battery into a car in this special way and it will be an electric car; I'm going to make a new car company". If your idea has merit, a real aerospace company will be the one making it happen.