engine VS unity-webxr-export

It's just a cool tech demo that pushes CSS to its limits, but it's completely useless if you want to create usable 3d models. If you want to model in the browser, you can check out vectary, playcanvas, or spline

The model in the video has no spheres, which is why the performance is decent. In any case, I agree with you for the most part, I'm just lazy and didn't expect anyone to actually want to use this for serious modelling. You should check out playcanvas or vectary if you are serious about in-browser 3D modelling

If you want the closest thing to Unity that's focused on browser-based (mobile and otherwise) development, try Playcanvas: https://playcanvas.com/

There are many engines that you can use in browser. 1. (GDevelop)[https://gdevelop.io/] 2. (Construct 3)[https://www.construct.net] 3. (Godot Engine)[https://editor.godotengine.org] 4. (Play Canvas)[https://playcanvas.com] 5. (Hex Engine)[https://hex-engine.dev]

Web-focused 3D engines (three.js, babylon.js, PlayCanvas, ...) are pretty capable. Maybe not AAA-level like Unreal Engine, but certainly capable of the stuff you're describing here. If you're comfortable working within these frameworks, and writing shaders, there's a ton you can do.

I wasn't familiar with PlayCanvas, looks very cool.

If so, this will be compatible with Unity WebXR Explorer ?

The WebXR spec is fairly well-defined, but has yet to be fully implemented into Webkit (the browser engine Safari uses). Currently the best way of creating WebXR content with Unity is using an up-to-date exporter such as this one by De-Panther, but there is currently no way to view WebXR content on iOS outside of Mozilla's viewer, which is unfortunately somewhat outdated now.