There are many videos on the TubeBuddy channel going over this, but I think you are asking a bit more of a "philosophical" question that I am dealing with as well, so I thought I'd share what I've learned so far.
TubeBuddy can help you optimize ideas you have, or to plan and select a topic. If you are optimizing an idea you have, it may just simply not have enough search volume or ranking to get you out of the red. I find that's where SEO optimization can at least maximize the traffic you do get.
On the other hand, if you are open to ideas, you can play around with search terms to find a topic that has the search volume and rankings.