Answer 1

Yeah. But not for backed development.
Html is for frontend development of Web pages and some 2d games.
Just pure html won't be enough for building a game ,as html just builds the “outlook”,you may need a programming language to build a working logic ,”javascript” is just perfect for it. So you need three things to build a game for now HTML,Javascript and some css (just for a decent appearance).
For backend development
You should learn
Javascript
Python
Java is not as good for game development as other languages like C/C++/C#. ... C++ is better because you can use it anywhere. It's the de-facto language of choice in game development. You can experiement with openGL and directX in it and most of the gameengines have either direct or indirect s
Good luck 😊👍