Is it absolutely necessary to do Nishkama Karma Yoga for Self-realization? If so, how should it be done?

Yes. You cannot understand and realize the spirit and object of Vedanta if you neglect to
practice Nishkama Karma Yoga for the eradication of the impurities in the mind. Nishkama
Karma Yoga gives you Chitta Suddhi and eventually culminates in the realization of the unity of
the Self.
Serve everyone with intense love, without the idea of agency, without expectation of
fruits, reward or appreciation. Feel that you are only a Nimitta or an instrument in the hands of
God. Worship God in the poor and…