Being an Acharya of an authentic sampradaya do you consider ISKCON sampradaya as an authorized one?

ONLY TO SOME EXTENT, YES. THEY ACCEPT “BRAHMA VAIVARTHA PURANA” AS SUPREME AUTHORITY. We accept that part of purana & only then, when and where it is not contradicing the Vedas. In Vedas it is clear that the ultimate GOAL of the soul
should be “so: dhvanah pa:ra ma:pno:thi thad vishno:h paramam padam” ‘Paramapadam of Vishnu’. This is only we accept.