First: make a prototype. If you can not do it, learn how.
No, really, just a basic minimum viable product. As you said, it should be simple. If some things are over your head, find someone to do these things for you.
Prototype manufacturing is cheap these days with services like JLCPCB or JLCNC.
Wobei es scheinbar sehr viele unternehmensspezifische tlds gibt: Wikipedia Liste
Natürlich auch .lidl .lego .Lamborghini .gucci .gallup .rwe .suzuki um mal ein paar zu nennen.