I built the initial version in about a week.

If you’re comfortable with react already you can use React Three Fiber, and a few libraries associated with it like drei. This can also be done with vanilla three.js.

I would say look for some 3D models you like on a site like sketchfab, and think of what you could build related to the 3D object. Even better, if you have some 3D modeling experience, create a model yourself and maybe a fun little website with it!