which is the jain temple in the varanasi main city having idols of kamath and dharnendra
The Parshwanath Jain Temple in Bhelupur, Varanasi (Varanasi city) is the temple you are looking for. It is associated with the legend of Kamathh and Dharnendra (Dharnendra) and is revered in Jain tradition for Parshwanath. Digambar and Śvetāmbar traditions both venerate this Parshwanath temple in Varanasi. You can read more about the Varanasi Parshwanath story here