Kulga I think you're right that it's not available. It's been an issue since forever but Flarum encountered issues with performance when trying to implement searching discussion titles, so I think prioritizing a solution to that is ahead of additional search gambits.
Seems likely you could add the gambit with an extension, though. And PR it to core if you're so inclined, but considering the performance issues with search on bigger forums, it might be useful as a standalone extension. (If you're not inclined to release and support an extension, check out what Clark does with kilowhat.)
