You are trying to tell us that it is impossible to chant the suddha-nama without having received gayatri mantra diksa.
I don't accept that to be true. Your guru may say it is so, but Mahaprabhu said otherwise.
diksa-purascarya-vidhi apeksa na kare
jihva-sparse a-candala sabare uddhare
Take Mahaprabhu's name off your list, along with the many others who you wrongfully say are supporting your apasiddhantic conclusions.
The soul is already pure and by chanting without offence we can reawaken our soul from the material dream the soul is currently engaged in.
krsna prema nitya siddha sadhya kabu naya,
sravanadi suddha citte karaye udaya
Sravanadi - by hearing and chanting we reawaken our soul from the illusion of Maya. Gayatri may be heard and chanted by the soul, but even without gayatri he can still become pure. Gayatri may not be necessary at all