I’m a person who doubts a lot in things like Najasa, Taharah, Wudhu, Ghusl etc. My Ghusl takes around 30 mins, so this should give you an idea of how much I doubt. I tried correcting myself but to no success so I wanted to seek help from a learned person like you.

Is there any aamal or dhikr to get rid of such doubts etc. ?

Its a psychological problem which can be treated by a psychatrist easily so please consult and get rid of this