You're touching on two Jain ideas: akasha (space) and siddhashila (the realm of the liberated).

• Space in Jain thought: Akasha is a tattva (an elemental principle) that pervades all space. It is not just a “physical space” like a room or a field, but a fundamental element that interacts with jiva (the soul) and with karma. So space is both a cosmological principle and a physical-like dimension, not merely a fairy-tale notion.

• Siddhashila: In Jain scriptures, siddhashila is the realm above the cosmos where liberated souls reside after attaining kevala jnana (omniscient knowledge). It is not a mere myth; it is described as the abode of truly free souls who are no longer bound by karma. These souls do not undergo further birth and death, and there is no continuing need to travel or move in the ordinary sense, because they are beyond worldly limitations.

• The question of motion after shedding the body: When a jiva sheds the body, its essential nature remains pure consciousness. In the state of moksha, there is no karma to drive movement or rebirth. The description of siddhashila emphasizes a state of eternal knowledge, perception, and bliss, rather than physical movement in the worldly sense.

• Is siddhashila “real” or “mythical”? Both Digambar and Shwetambar sources discuss siddhashila as the genuine dwelling of liberated souls. Descriptions and nuances may differ in elaboration, but the fundamental concept is shared: moksha ends cyclic birth and grants residence in a karmabindless, blissful state beyond ordinary travel.

If you’d like, I can share the exact Sanskrit terms and their meanings from Jain scriptures, explained in a way that stays faithful to Digambar and Shwetambar distinctions.