Hello,
I have gone through your requirements, Currently you have Subject list -> topic list -> than videos & You want it like category wise view like Hotstar for minimize users efforts to access videos.
So, You want a page were subject wise topic is displayed. so from single page user can see all topics of all subject.
Yes, I am able to complete this task. As I have a expertise in android development its very easy for me to do this task.
I am fresher on this platform But I have worked on more than 25 android application in four and half years of my professional career.
Let me know if you are interested, I can start it right now & complete by today itself.
Thanks,
Hardip