I like this!
What about something like this? If after you typed [[ and the link suggestion popped up, there was a way (a hotkey maybe?) to invoke any of the search operators.
I like your idea of using different symbols too.
For example, if a note “Apple Recipes” had the text “muffins” in it:
- type [[ to start adding a link.
- hit that special hotkey (or type {{ instead like your suggestion)
- type content:muffins
- You see a result that looks similar to search
- Hit Enter, and it adds the link to the file, “[[Apple Recipes]]”.