How to add Blots under each paragraph

问题:

I'd like to have under each paragraph in the editor an emoji that can't be edited/deleted by the user (but can be clicked).

It seems that Blots are the direction to take, and https://stackoverflow.com/a/55616254/750039 seems to be the direction.

However in that question the Blot is added regardless of the content. In my case:

1. when the editor is empty no emoji should appear.
2. When paragraphs are being written - different emojis should appear under each and every on of them
3. When a paragraph is deleted, the emoji should disappear as-well