I'd throw out webpack and start with unbundled ESM today. Vendor bundle and spot bundle with esbuild or rollup or something else designed for native ESM bundling and just ESM bundling, and only where you see actual performance bottlenecks (visible request waterfalls). Use any friction you see as an excuse to replace/drop old CommonJS dependencies entirely.

Webpack had its day, but today its kitchen sink and incredibly baroque configurations are as much a liability as a helpful place to start on a project. Start fresh with ESM and without a bundler and things are surprisingly nice in development experience.