It doesn’t seem like the repository has that many contributors to begin with, so I would think the answer to improving the bus factor begins with getting more contributors.

Something that might help bring in more people is making it easier for a new contributor to build it locally. I don’t enjoy dealing with Java/Kotlin projects because the tooling is pretty messy when compared to the tooling for Rust projects. Perhaps a dev container and/or a Nix configuration might help with making that easier? I know it would for someone like me.