How do you make fancy websites like these with cool scroll features and 3d graphics?

At the moment, I can only write HTML, CSS, a bit of JavaScript and PHP. I am decent at 3d design and animation in Maya and have some experience with Unity. What skill set do I need to be able to design websites at the following level? How are these websites designed, and what language could they be written in?

Cool 3D graphics:

https://www.luni.app/

Cool scroll features:

https://45r.jp/ja/indigo-hakusho/

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