Probably worth a submission on its own but I am just waiting till it is fully open source.
Edit: ( Deleted those Stats, since it may not be a fair comparison and it was probably not meant to be a fair benchmark in the first place. The details are still in the linked tweets. I do not know the author or am I in anyway affiliate with Bun. )
I am also wondering how much of those optimisation could be used on ESbuild. Since Rails 7 and Phoenix 1.6 will be using esbuild and not Webpack.
[1] https://twitter.com/jarredsumner/status/1390084458724741121