I’m 75, and much less diligent about making certain I use all my electronic aid and toys correctly than I was when younger. So I’ve not figured out the ideal way to use my KS10s with my iPhone. The HAs pair pretty easily with my LG OLED tv ( in fact, the sound quality is good enough that usually I don’t bother fetching my Apple AirPods Pro for private auditioning of TV programming. Using the HAs for tel egg phone calls is another matter, because I can’t remember to avoid raising the iPhone to my ear, which is preprogrammed as a “smart” (idiotic, rather) gesture for the Siri BOT to do something, which may be to divert sound TO or FROM the HAs to the phone, or even hang up the call if I bump my phone against my ear twice. Sound quality is fine, and if you can train yourself to keep you phone away from your ear the microphone in the HAs do a remarkable job of carrying your voice to your caller. Now, if you also have an Apple Watch, your calls may ring on your phone, your wrist, your Tablet, and even your laptop and desktop computers will all ring st the same time!
The other issue of course is that right now the KS10s are no longer in Costco’s products for sale list