I’ve had good luck splitting the difference by writing custom, dependency-free build scripts. You never get this accelerated code rot when you depend only on a mainstream language, it’s pretty trivial to implement a primitive version of bundling, inlining, macros, etc, and being primitive is far less limiting when you’re developing your build script hand-in-hand with your code.

Some things can’t be done like this, like TypeScript, for which I keep it to a minimum, look for stability, and often include a full copy in revision control.