All of your points are wrong, if we look at your first point that he signed under dubious circumstances, then who created that circumstance? Pakistan Army with Pashtoon irregulars attacked J&K and when Mahararaja’s Army was unable to stop them then Maharaja came to Sardar Vallabhbhai Patel and asked for help for which the condition was put that Indian armed forces is for the protection of the Republic of India and can not operate on foreign soil, so you’ll have to accede with India so that Army can operate there, after which Indian army pushed back the Pashtoon irregulars to a boundary called cease fire line which today is called LoC.
Your 2nd point is partially incorrect, I feel you should read it once properly.
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And your 3rd point is also incorrect, simla agreement signed between India and Pakistan after the 1971 war clearly implied that:
So J&K issue has to be bilaterally solved and UN involvement or any other 3rd party involvement is not acceptable to both sides as per the resolution.