Adinath Bhagwan and Rishabdev are not two different persons. Adinath (Ādinātha) is another name for Rishabhanatha (Rishabhadeva), the 1st Tirthankara of Jainism. In short: Adinath = Rishabhanatha. The term Bhagwan is an honorific title used for Tirthankaras.
Key points you can remember:
- Names: Ādinātha, Rishabhanatha, Rishabhadeva, Nabheya are all used for the same great Tirthankara in different texts and traditions.
- Role: He is considered the founder of the Jain spiritual order (established the fourfold sangha) and the first teacher who set forth the path of right faith, right knowledge, and right conduct.
- Life focus: Renounced worldly life after a long period of penance, preached across countless beings, and eventually attained kevalajñāna (omniscience) before moksha.
- Traditions differ on some details (such as cosmology, hair practices at initiation, and minor biographical details), but the core who he is remains the same.
If you’d like, you can read a concise Jain-focused account here: