I relate to you and understand where you're coming from. I mean, I'd substitute power for fame (e8 vs e3 preference), but that's about it.
I have a couple of thoughts on this. Like you, despite ambition and a strong drive, I was in many ways a kind of empty vessel. I had a general idea of what I liked and what I didn't like and what my strengths were, but no clear burning desire to become one thing. Our instincts are to lead and organize, but we're not necessarily particular as to what. Because to us, it really doesn't matter-- Ni renders certain principles universal.
I think it's hard for ENTJs because we're Fi last, so our personal feelings on things can frequently be a blind spot. There have been a couple of things that have helped me develop Fi that I'd recommend for you to try. The first would be connecting with people who use Fi better than you do, explaining your problem, and asking for help. I've been blessed to have a lot of really tremendous NFPs (and even an INTJ or two) in my life who have taught me a great deal about how to navigate some of my inferior Fi issues, and I'm a lot better for it. Having a deeper appreciation for Fi will help you determine what's really in your heart, and will help you know how to attain those things in a way that's right for you.
The second thing that has been crucial for me has been learning to meditate. Having an introspective practice like meditation helps you to figure out what's going on with yourself (Fi), and strengthen your connection to your inner guidance (Ni).
Last bit of advice: focusing on fame is counterproductive, honestly. You should focus on simply being excellent, and recognition will automatically flow from that. If you focus on the recognition and external validation first, it fucks up your priorities, and that "empty vessel" thing we have as ENTJs will degenerate into outright hollowness. Do your best, strive as hard as you can, and shit will turn out the way it's supposed to. No more, no less.