People often talk about finding a "gap" in the academic literature, but this isn't always the best way to develop a research project.
Even if you find a gap in the literature, the mere fact that nobody has published on it isn't enough to make it interesting to other academics (and it has to be of interest to others in order to get published).
Sometimes, the best research is done where there is already a huge amount of literature; where we think we know something but it's perhaps based on a widely accepted but flawed or untested assumption.
Other times, it could be about finding an interesting edge to work on; taking existing research a little further or taking a different approach to the same problem.
So a gap in the literature isn't really what you're looking for. You're looking for an opportunity to develop a meaningful research project. The relationship between that project and the existing literature could be complicated.
For more on this, check out this post from 2017!