Having just used to new enex/html import function to get all of my old Evernote notes into Joplin, the final final piece of the puzzle, now I have several thousand notes, is a more nuanced search. For my use I don't think I need to start building crazy complex searches, but being able to restrict to notebooks and tags and to specify text in the title would be ideal, possible with negation, e.g.:
notebook:project1 tag:priority test*
i.e. run the regular search, but restricted to those notes in the project1 notebook which are tagged as priority. Or:
intitle:summary notebook:project2
i.e. those notes in project2 with summary in the title.
I rarely need to negate searches, but I can see that as also useful. The only other thing that for me would be great would be to search add a search for notes containing un-ticked "to do" items, e.g.
notebook:project1 todo:false
or similar. See also the discussion in: