Building pnpm monorepo to single file AMD in vite

Question

I want to use a library that's build as a pnpm monorepo producing a set of modules. I want to use this library in an older requirejs project, and my goal is to build the entire set of modules and all of it's dependencies to a single javascript bundle with Vite. I've tried some tooling provided by requirejs called r.js to try and transform the modules to AMD, but those tools are outdated and don't work anymore. So now I'm refactoring the vite.config of the library to try and build it to a single bundle.

I've tried to change the rollupOptions so that no externals are present and I disabled manualchunks (as recommended elsewhere) to force everything into one bundle with no success.

rollupOptions: {
  external: [],
  output: {
    dir: resolve(dir, '../test'),
    manualChunks: undefined,
  },
},

What should I do?