What are the Best languages to learn web dev other than HTML CSS and JS?

Answer 1

You must have a basic knowledge of HTML, CSS and JS, because those technologies are the only ones understood by web browsers, so it's critical for the client side.
(Yes there is also webassembly - WASM but it still counts as cutting edge technology and not used very widely.)

However you can use many languages to develop web apps, even full stack. PHP, Ruby, Python, Java, C#, Kotlin, and many others all have advanced frameworks which are able to generate html pages for you from templates, based on back-end logic. You can even use JavaScript on the backend with Node.js.

Saying what is the "best" is very subjective, everyone will recommend you what they know and they are familiar with. I would say that choosing the best language often depends on the project requirements.
If you mean best for finding jobs, you should look around on the job market, and ignore the actual qualities, pros and cons of different languages, because in real life, often many suboptimal and obsolete solutions are used by companies.

Answer 2

C++ or Java