You cannot legally publish a game on Steam or the App Store using assets from an unofficial repack. You must own a seat license for each asset via the Unity Asset Store Malware Risks:
Assets like medieval villages, modular mansions, or stylized sci-fi landscapes. -REPACK- Unity Asset Bundle 2 Mar 2019
Unity is notorious for breaking changes between versions. An asset designed for Unity 2018.3 (current in March 2019) might throw dozens of errors in Unity 2022 or 2023. Developers working on long-term maintenance for older projects often hunt for older versions of assets to ensure they don't break their build. They aren't looking for the "latest and greatest"; they are looking for the exact version that worked with their codebase five years ago. You cannot legally publish a game on Steam