I recently wrote a mini tool that servers as a unused and duplicate dependency checker. It uses golang and esbuild under the hood so is quite fast.

It also built to support monorepo, something I found a lot of tools didn't support well.

It is fully open source and you can try it out https://github.com/CryogenicPlanet/depp

Fair warning, it is likely quite buggy and might have some issues and it is very new but it worked decently on our internal codebase