Coupling (potential) whiteboard with (potential) annotations

Note: it's quite a long-term, as it requires both Whiteboard / Canvas feature and PDF / Media feature to be implemented first, before they can be coupled. So I'm just leaving this idea here for now to be considered in a long term.

AA user, I want to:

• have a page with PDF (or Video / another media) and my canvas (or mindmap) both open and visible
• once I add an annotation, it appears as a block on canvas
• I can organise those blocks into a mindmap (parent-child connections + two any blocks can be connected with each other), which allows me to organise the annotations from the media into a structure
• once I click on the block containing an annotation, it scrolls the media to this annotation, so that I can always get more context on it
• ideally, I can turn on a focus mode on some block so only it and its children will be visible on the whiteboard

A really good example of this idea is MarginNote 3.