Question WebXR: Support headset, mobile and desktop?

Is it possible to create an app in Unity and have it support WebXR/controllers on headsets, WebGL/touch on mobile and WebGL/keyboard/mouse on desktop in one app bundle? In Three.js this is fairly straight forward by forking code depending on the platform. I know Unity is not ideal for web because of the large file size but I just want to know if it's an option.