I've gone through a similar experience with Rails 5.1 which has, having ditched jquery, gained support for webpack, babel, yarn, and vue.js (& react) instead; and thereby made writing JavaScript an order-of-magnitude less painful for me.

I feel that ES6 is a palace built on the ruins of a garbage dump and an odd stink still leaks through from time to time, but like the author, I can work with it now without loathing what I'm doing.