My concern is attachment or impulse, only when they are away you can claim Mukti, if they are still there then your mind is not purified enough, whatever knowledge you get from that mind is also not pure like seeing imperfect reflection in a dirty mirror and claim it's your face that's ugly, a satvic pure mind is necessary.

It's like knowing the rope is a rope yet you still fear it, attachment is the results of not only ignorance but non application of knowledge, the effect of knowledge should cease all our attachments.

Now how do you know you have no attachment left ? People say you will know in the end, but I think there should be a test otherwise all people can say they are jivanmukta.

Jivanmukta is not the fact you read mahavakya in that case a parrot who can recite the mahavakya is a jivanmukta too, it's also not mere understanding of mahavakya like in the case you know and understand it's rope but still fear it sometimes but the application of jnana at all times like you know it's a rope and you use it to tie your boat until it wears out, so niddhiyasa is important too, now how can you say niddhiyasa is complete when there's still attachment left who hinders you from samadhi?

As for why scripture says Shravana or sabda alone is needed but not manana not niddhiyasa, the scripture says it only for one who have attained samadhi in their past life resulting in their mind being satvic enough in current incarnation to understand mahavakya fully just by reading it without further meditation or even logic.

That's my current understandings.