After reporting the watermark missing bug, I think why not make the watermark even useful. So I come with this idea. Of course this feature is for FULL version users.
A customizable watermark options, in settings, and allow to adjust where the watermark shown, what the watermark is (load from external file), and a transparent option. This option is shared project-wise so put this in settings is fine.
If someone want to add watermark in pictures or video, they don't need to open another software to do that if the watermark is customizable.