Looking back at it, thinking that I had come up with a tool that hadn’t really been built yet, in this day and age is kind of crazy, I guess?!
It helps to realize it's not being the only person working on an idea that makes the idea promising. Any idea that's promising will have several teams working in. So if what was deterring you is competition, don't let it deter you. And if there was no competition you should be alarmed.
what If I am supposed to put time, energy, and money into the other ideas?
Constrain yourself to not working on any specific idea until at least two weeks have passed. Not only is it OK for new ideas to surface in the meantime, but it's also something that you want. You don't want to stay stuck working for 6 months on a less valuable idea. And it's not a contradiction to have other ideas, but a healthy path forward. Plus, if you are not having enough stupid-sounding ideas you are probably being too conservative.
If I were to give you only one piece of advice, it would be: describe the whole idea in a short sentence, preferably under 5 words. If you can't do that, you don't know well what your idea is. And that's a much bigger source of concern than competition.