The quality of exported PNG files depends on your screen resolution, so it's a screenshot of the canvas. The screenshot which often not contains some information that you need: meta module when there is a bug or you zoom out too much, no pinned comments, etc. I have an FHD display and exporting to PNG doesn't make any sense to me. If you have at least 2 small ICs and some passives around them and you want to capture the whole schematic in a single PNG then all text will be unreadable.
I am proposing to add an export to PDF. PDF that will contain all data like pin names, comments, etc