What Chrome version are you using on Android? Have you tried the native WebVR support: Vr Eye Distance - #19 by wojtek ?
iOS blocks website access to device motion and orientation sensors by default. Starting from iOS 13 a website has to ask for user’s permission to gain such access. Permission request is already implemented for scenes on our hosting (could you try opening some of your scenes from there?) For self-hosting it will be available in the next Shapespark release.