So generally a quick way to prevent that sort of stuff from happening on mobile is to tack this CSS onto the elements in question (canvas, img, etc):

    touch-action: none;
    -ms-touch-action: none;
    user-select: none;

That should prevent any touch related actions and accidental user selection on devices.

See MDN for details on each:

https://developer.mozilla.org/en-US/docs/Web/CSS/touch-actio...

https://developer.mozilla.org/en-US/docs/Web/CSS/user-select