I can't seem to find anything definitive about whether WebRTC (or some subset of features) is supported in Oculus Browser 12.0, and I don't have access to one to test myself.
According to the Oculus Browser 12.0 release notes, it uses Chromium version 86. According to the WebRTC Wikipedia page, Chrome has supported WebRTC since 29. So that seems promising. But caniuse.com says that it's only supported in 87 (unless I'm reading that wrong...). It's unclear to me what the relationship is between Chrome, Chromium, and Chrome for Android. Just because it's "supported in Google Chrome", does that mean it's supported on all platforms? Are Chrome for Android and Oculus Browser basically same thing for the purpose of which APIs it supports?
Thanks in advance!
WebRTC does work in Oculus Browser.
I'm not sure why caniuse does not have data for Chrome for Android before 87. WebRTC was implemented in Chrome for Android in 2012 and shipped in 2013. Here's the old launch bug for WebRTC on Android in the Chromium bug tracker.
Google Chrome and Oculus Browser are different browsers, but they share a lot of code from Chromium. One browser supporting feature X does not guarantee that the other browser does, but it is usually the case.
If an API is not core to your experience, it is good to use feature detection and degrade gracefully if an API is not implemented on a browser you're on.