Has anybody been able to join another table using SearchCriteria, JoinProcessor and virtual types. I have read the documentation (https://devdocs.magento.com/guides/v2.3/extension-dev-guide/searching-with-repositories.html) but for me at least it is very hard to grasp. Also, the example on the Join Processor described in the documentation page, which looking through the code is also the only implementation of this kind, is soooo vague and hard to understand (seems almost experimental).
So if there is anybody who did this or who understands how this should be done, can you please provide more details into it?
P.S. I think that understanding this concept can add much value in terms of leveraging the ViewModel concept even more and decoupling the Block classes from the templates (ex: at this point if you want to perform collection joins and add pagination for the results you're pretty much tied to the Block class and the _prepareLayout method).