What is the scriptural basis for the idea that the proces of KC and not the guru transforms us?

From Vaishnava Charan Pr

1. The balanced approach theory which you have suggested, can it be supported by any quotation and/or instruction by Srila Prabhupada or any other bonafide Acarya from our parampara of Gaudiya Vaishnavas?

2. How can we understand that KC process is ultimately what is going to transform me and not Guru?

In the great song by our acarya Srila Vishvanath Chakravarti Thakur, which we chant every morning: it is clearly said

Yasya prasadat bhagavat prasado, yasya prasadat na gatih kutp api

“By mercy of spiritual master i get the mercy of Krishna and without mercy of Guru (i.e bonafide), i can never get mercy of Krishna.”