I’ve found FrontendMasters to be the best resource for intermediate-advanced courses in the JS space. Even their stuff that covers the basic subjects (HTML/CSS/JS) does so from a position of industry best practices.
It is a little on the pricey side ($400 per year).
Wes Bos and the Reacttraining courses are also really solid next steps, both a bit pricier than a lot of the “bootcamp” style courses. But you get what you pay for.