Doesn’t that example also make it impossible to minify the names of anything? Perhaps other than JavaScript modules, since AFAIK the popular module builders like Webpack do compile-time module importing (I believe that even the dynamic import function is recognized at compile time and doesn’t support throwing in a prompt).

No, that issue is unique to class/object property names. You can't dynamically reference a variable in a scope by name supplied by a variable in the same way (except by using `eval`, which does in fact cause minifiers and javascript engines to disable a bunch of optimizations in the scope it's used).