Which programming language is best for 3d multiplayer games?

al
1

Wants to learn a few languages and wants to know which programming language is best for a game like fortnite or gta online

Is

HTML is a markup language, IntelliJ is a development environment and you will not reprogram GTA Online alone. Especially not as a programming beginner (and you are, otherwise you wouldn't make the mistakes mentioned at the beginning).

I would ask the opposite question and take a programming language that I already know well and then google what 3D / game engines there are for this programming language.