How can I master in each and every subject

You can, but it's not what someone should always intend as a Student. As a teacher, it's a different case as you are not bound by time (1 year for all subjects). Each item requires a particular thought pattern. Any student who is excelling in all matters is either using a lot of memorising. Hence, creativity and analytical thinking is hampered or comes from a family background where somehow he/she gets leverage over all subjects (e.g. travelling, open-minded, early subject introduction, etc.).
The second one is a rare student as any student who has gained enough wisdom will choose "Insights and Details" over "Memory", i.e. they seek to gain "insights" into the subject which leads to mastering the issue "in a long time" and not "memorise" it to learn the "in short time". Well, a motivated one can do anything that's for sure (i memorised the whole periodic table in class 8 because of a bet with my sister who was in 10).
My point is,
As a teacher, you can master all of it for employment purposes. Still, as a student I would advise not to take such a path as the present world asks for skills and how rich you are in a few subjects and how much can you apply all of it and "work with others" for the remaining as they are your limitation rather than being a hard disk for all.
BUT ALWAYS GIVE YOUR BEST
There is this one amazing thing I remember from Jack Ma, "An intelligent person will always have a problem working with others." 🤣
Hope you derive some better thoughts from this

if you want to become SME (Subject Matter Expert), first desire yourself, nothing is possible once you fixed in your brain. Telling is different & implementing is different. If you should be set (Burning Desire) this is my life path; there is no alternative way to reach my goal, you feel like that. You can achieve.
Nowadays, so many resources are there in the current market, you Utilize them, SHARE them, implement them what you learnt..!
Resources are Expert teacher.
Our best friend: Google etc. practice the objects, you will get no. Of factors, will get different methods (ways).
I practically observed, Most students have excellent knowledge, but they don't know how to Utilize it ...
Seriousness.
Time sense and proper schedule etc. are critical points for LIFE.
I wish you all the best.
Best Regards :
SHIVAKUMAR
Asst.Prof &
Former Software Engineer (SAP ABAP Consultant)