I also tried keeping Webpack and switching to Bun with no other changes. This made the build 10s slower. However it made installing packages like 100x faster (not an exaggeration).

The ultimate gamer move will be to use Bun + Vite down the line, but currently Bun does not support Vite's hot reloading and Vite does not use Bun's streamlined bundler yet. However, it is planned.