SWC doesn't bundle at all. Esbuild is a pretty good bundler but works well only if your code and dependencies use ESM, it's not as good as other options with CommonJS.
While I haven’t tried Mako, it seems to have support for advanced code splitting[2]. No idea how powerful its plugin system is.
I cannot attest to that. We are using Esbuild plus CJS at $DAYJOB no problem. Why would that be an issue?