I like "Javascript for Impatient Programmers": https://2ality.com/index.html

If you mean ES6 as "modern" JS, then you might want to avoid any material on prototypical nature of "true" JS (which it still is under the hood). Personally I find classes and modules to be very useful.

Although you say you don't care for DOM, CSS and the many frameworks, you might need still need to build a small HTML file to kick start your JS programs. I do all my exploring and learning in Chrome's DevTools console and debugger. JS is not that difficult to learn if you already know a curly brace language (C, C++, C#, Java, etc). Even after years of working with JS, fiddling with DOM still catches me off guard on occasion.