How do you separate the confusion of not having an edge vs not knowing enough about the market?

I am currently listening to “Trading in the Zone” by Mark Douglas, and in chapters 6-7 he talks a lot about trading psychology and being confident in your edge, but at the same time, talks about how if a trade goes in the opposite direction, most traders revert to trying to learn more about market analysis and get trapped in a vicious cycle.

I’ve been paper trading for a small amount out time and even with emotion removed, stop losses, using support and resistance, following trends, etc, it feels like I still end up at a loss.

If you’re profitable, how did you find your “edge”, how long did it take, and how did you know that your edge was a good strategy?