Yes, it supports Roblox VR. My kids adore playing VR Hands.

edit - here's the process, although most steps are already completed if you actively use your headset.

https://www.lifewire.com/play-roblox-on-oculus-quest-or-ocul...

No, but you can access VRland which is sort of like a web-based VRChat. Social 3D/VR via WebGL, WebAssembly, and WebXR that works cross-platform via the browser, not just limited to headsets but can be accessed via phones and computers.

Link to try it here: https://vrland.io/