Short answer: There is no next kevalin after Jambuswami in the present time cycle. Jain tradition holds that Jambuswami was the last Kevali (omniscient) in this avasarpini, so no one attained kevala jnana after him in this cycle. After him, only Shrutakevalis (scriptural omniscients) are mentioned in different lineages, but not new Kevalins. ( jainknowledge.com)

If you’d like, I can share a brief note on how different Jain traditions describe the Shrutakevalis that followed, in simple terms.