I've had connectivity problems that I'm hoping are just related to iOS versions. While Apple says 16 is "required," they also acknowledge that's just for certain features and that the product will work down to the iPhone 6S, which tops out at 15. These are Bluetooth peripherals, after all. I started off connecting them to my iPad Pro running 15 and my 6S+ running 13, and while I could connect to both, the connections were unreliable and sometimes hard to reestablish. Updated the iPad to 16—still, it doesn't like it if I've used the phone with the buds then come back to the iPad. There are also issues with sound and transparency when listening on the phone.
This really shouldn't be happening, IMO, though I'm hoping that there's just something about the lower OS on the phone that throws them into a fit, that would be resolved if the phone was also on 16. (Unclear if bumping my phone to 15 would help at all, given the experience with iPad on 15.) I'm going to keep experimenting with my wife's (up to date) phone.
I will admit it will be pretty silly if I end up replacing my entire pocket computer to the tune of hundreds of dollars over some earbuds, but I've held out for a long time as it is, and here we are. (How's iOS 16 running on the 8, anyone?)