What is the best way to migrate to Angular 6?

Question

Angular

Good afternoon. We are going to translate an existing project to Angular 6 and a logical question arose as to how best to do this.
Current versions of Angular 4.3.1 , Rxjs 6.2.2 + rxjs-compat , Typescript 2.4.0 , Webpack 2.6.1 , we do not use CLI, we have our own build configs. The 6th version requires webpack 4, as well as Rxjs 6 by default in the angular itself, and the angular2-template-loader has stopped working, or almost does not work, in general, a lot of changes. The question actually is whether it will be better and painless to transfer the project to the Angular CLI and work under it, or to rewrite the webpack config, google plugins, and so on. ?