Here's an open secret that might make you feel more comfortable: you can launch as many times as you want until people notice. Here's an awful public launch: https://news.ycombinator.com/item?id=13343276. There's no signup, buttons seem not to work. Nobody's going to care/remember if they try again when the app is more baked in a couple weeks.

If you're not sure if your thing is usable, find someone who you can watch use it in person.