Not sure how it holds up, but Secrets of the Javascript Ninja was the book I read when I felt like that, and it significantly helped me understand a few concept

Not sure how it holds up, but Secrets of the Javascript Ninja was the book I read when I felt like that, and it significantly helped me understand a few concepts I had struggled with. By John Resig (created jQuery). But it's a few years old now, so likely won't cover much if any ES6+ stuff. But I'd bet the concept stuff is still very valid. Also the You Don't Know JS series. And Elliot's Programming Javascript Applications. I don't know you, so I don't know if this applies or not, but be careful not to fall into the "expert beginner" trap (i.e. Dunning Kruger). Your first sentence starts to feel that way, but the fact you're asking for more resources and aware there are things you don't know are good signs. Always keep learning, the rabbit hole goes ever deeper.