The developers are passive-aggressive to the notion of rendering Quill content outside of the Quill Editor, having ripped out the APIs to do so from newer versions, and silencing conversations in their Github Issues.
You can see the latest flare-ups here: https://github.com/quilljs/quill/issues/993
The project also has secondary smells such as inventing weird names for existing concepts; 'Delta', for example instead of 'data source' or something more intelligible.
Lastly, it markets itself as feature-complete, but has failed to implement support for something as basic as tables, which have been repeatedly requested for the past 3 years.
Personally, I would be afraid to build anything mission-critical upon it.