Answered[ Edited ]
I had the same issue! I remember reading an article many years ago about how all shampoos basically do the same thing. In my own experiences, I've come to discover this to be true.
I usually stick to cheap-yet-gentle shampoos like generic brand baby shampoo, then invest in a good conditioner or give myself a hot olive oil treatment once in a while applying either on just the ends of my hair to keep things balanced. Remember, if you strip too much oil, your body will produce even more to make up for the loss.
I hope that helps!