I spent some time in 2022 working for Magnopus on their 'connected spaces' metaverse platform.
Now it's been made public, I can say a little about it.
I joined shortly after they transferred their web renderer from Babylon to Playcanvas. That was interesting, partly because Playcanvas seemed to perform a lot better, partly because they didn't benchmark Three.js as well, and partly because they used the open source component of Playcanvas, not their web based IDE.
A big selling point is that they're maintaining parity between several platforms - Unity, Unreal, IOS and Web. This alone is an incredible feat of engineering.
Another quite amazing feature is the ability to write JS in the environment, on multiple platforms. And because of that restriction having to use an alternative to the JS V8 engine for running code, even on the Web.
Note that these features were in development at some point, final release may differ.
Still, a very ambitious project, and well worth keeping an eye on. They will likely be, along with Meta, Niantic etc, one of the big players in the Metaverse space.