Nice work!
I've actually been using a similar approach while preparing for interviews, and it genuinely helped me land my current job.
One thing I realized along the way is that mock interviews are only part of the process. Before practicing, most people still need to figure out what to study, in what order, and where their knowledge gaps are. That's the idea behind Dumqa—helping people prepare before they even start mock interviews.
I think the two approaches complement each other really well.