How to develop discipline over motivation.

This is my first post here on reddit. Currently in class 11th, studying at aakash pitampura and place around top 5 according to tests (which dont prove shit) in my batch (top batch in centre).

I had got anthe air 100 and was selected for COE exam (a seperate branch for ranker students) in 10th but i could not clear it due to my branch telling me the exam date later than it was and i couldnt complete the 12th and 11th syllabus.

From covid, i used to cheat my parents and played video games behind their back and told them i am studying (this habit still sticks with me, even though it is much improved since i actually study now..)

This led me to waste my 9th and 10th playing roblox.

Now i have quit roblox since 11th. It is my dream to get air top 50 and my target to get atleast air top 1000 in neet. I want to become a neurosurgeon abroad as my father (AFMC grad) couldnt go abroad due to personal reasons.

However i constantly watch aiims delhi campus tour and aiims delhi vlogs for motivatiom, which is cheap dopamine.

I have stopped watching videos but somewhat find it difficult to continue without motivation. For motivation i keep reminding myself about life at aiims delhi.

How do i develop such unbreakable discipline that even in my lowest days without any motivation i can study effectively (I have to-do list which i have to do before i sleep and a routine which i dont follow. But i do follow its general idea).