@Greg Be careful -- a significant number of bluetooth headphones/earbuds now require proprietary apps in order to do pretty basic things. I wouldn't exactly "recommend" PineBuds, but they work and have the promise of flashable firmware. Definitely plenty loud :) As a person who fundamentally doesn't like not being able to hear ambient sound, I also really like bone induction options.
@mlinksva @Greg I'm not actually totally sure having never bought a pair that required it, and the requirements seem only sketchily documented because everyone assumes you'd just be okay with an app. But I know when I was looking last year I saw things like needing the app to turn noise reduction on/off and to change sound profiles. Maybe also to only use one ear at a time (something I do frequently, see above about ambient sound). I don't think it's an issue in the < $50 range.