also is there anything like Mini map, Full screen, zoom level are in the roadmap?
You can annotate in a published mobile app, including one that contains ValQ. Here is a basic video showing the steps for how to do it in Power BI in general.
You can use the mousewheel to zoom in and out as well as the slide at the bottom of the canvas. On mobile a pinch will zoom in and out.
The current developer version has a whole tree level expansion control on the canvas (so coming soon).
For now, we can add Node level comments in Edit mode, which is more like a Technical note at the developer level.