indexing nested fields of selected entity ref field

Thanks for suggesting this feature!

While we cannot really change the behavior when marking a field for index (since that would break people’s configuration), this does sound like functionality that could be implemented in some optional way – for instance, as a processor.
However, I fear that I currently don’t have time to work on feature requests, except in an advisory capacity. So, if you want to propose a patch (please remember to include tests), I’m happy to review it. (Or provide pointers on where to start.) Otherwise, we’ll have to hope someone else comes along and provides a patch (or hires me to do it).

That being said, if this is just about getting all the fulltext contents of a paragraph (or the entity that includes it), the recommended way of doing that is to add the “Rendered HTML output” field to the index, which will also (depending on the view mode, of course) include all the paragraph data attached to the entity. (For optimal results, create a new view mode without any field labels, images, etc.).

as the Rendered HTML output solves it for me, u can choose to close the issue.
This feature would be useful though when not wanting to index the whole content of the entity