I feel exactly the same as you do — JavaScript just doesn’t seem to work for me. I know Ruby and Python, and html and CSS, and yet with JS I seem to be having a mental block. All I can say is this: Repetition matters. The more you solve exercises, the more small projects you build, the more you read and re-read some books, the more these concepts will be picked up by your brain. Our brain is a muscle and it needs some exercise 
I think the algorithms, as one of the posters suggested, are definitely a good way to practice your understanding of the language, because you’re solving a small problem with the tools at hand. I find those really tricky, but don’t get discouraged, even if it takes time! Wish you the best of luck 
I’m in there to. Did you get to write out the 1st Practice before seeing the authors answer? It took me some time as I was in another level with it. Creating various functions to be called in a sense of a loop for the way I made it was not to get looped in the real world (still working on that part as they say to practice with what you created and modify it) and I watered it down to the way it was to be made in a beginners level. But not at a beginners level, but at a level based upon what @saturnsbelt703 may be looking forward to (I’ve gone through various studies of javascript beforehand myself via Codecademy under some guidance within The Odin Project. Moving forward, I got the study within this Guide (where coding is starting to make sense):
https://forum.freecodecamp.com/t/computer-guide-computer-science-and-web-development-comprehensive-path/64470
I totally get you. But this happens with almost any material I study. The real progress comes with practicing what you learn, get yourself some personal projects or implement some ideas. Look for simple stuff you can solve using software and the skills you know, or simple games. Learn from tutorials by coding side by side with the teacher, mess with the code. Ask people if you can build something for them -get in trouble, or calculated trouble. And then try solve the problem or present a solution. Go nuts, struggle, feel uncomfortable, but also enjoy what you already know by doing fun stuff with it.