When you're unsure of your value in a particular field or the true demand, the only solution is to build volume.
For example, if you're unsure whether you can compete in the market on your own, you need to increase the frequency of your attempts. If one doesn't work, try again, at least ten times. Only with sufficient sample data can your analysis be effective, and the resulting improvement measures provide practical guidance.
After one or two attempts, relying on luck to change your fate, and hastily judging your value as low if the expected results aren't achieved, is a form of self-isolation and regression.
This doesn't mean you're truly incompetent; it simply means you're weak and lack the will to fight.