why am i stuck at 1200 blitz rating ?
"why am i stuck at 1200 blitz rating ?"
++ Play 15|10 rapid and analyse your lost games.
When you get good at that you can come back to blitz if you want.
"i've tried to learn new openings such as Karo kan and Queen's gambit or indian king defense"
++ That is a useless waste of time and effort and will not help you in any way.
Instead study endgames: that will help you much more.