Parshwanath Bhagwan at Shankheshwar (Sankeshwar/Shankeshwar Parshwanath) is described in Jain scripture sense as an extremely ancient Mulnayak. In the JainKnowledge.com page for Shree Shankeshwar Jain Temple, the Mulnayak Parshwanath is stated as “billions of years old,” reflecting the traditional Jain view of Tirthankara idols as timeless, cosmic principles rather than dated stones. This kind language is common in devotional Jain texts to express the eternal nature of the Tirthankar. Different traditions (Digambar vs. Shwetambar) may emphasize different legends or phrasing, but the core idea remains: the idol is an ancient, eternal embodiment of Parshwanath. You can read more here