(***I can't adjust the volume of an earpiece speaker during calls, also while listening voice messages on WhatsApp etc. It is only about the earpiece speaker, not the main speaker and sounds. I contacted Apple support and tried factory reset and diagnostics, but it doesn't work. How can iPhone users have this issue, my phone is very new. Even with cheap android I never had such issues. But the most expensive phone has it. It is just super annoying.)***
I also tested this with other phones which run on IOS 16 and had the same issue there. But phones with older IOS don't have this issue. I'm not sure if it is an issue, maybe Apple developers thought that it is a useless feature and they disabled it for Whatsapp, Telegram etc. But I use it every day basically. I receive dozens of voice messages on Whatsapp, and everyone has a different tone I don't carry earphones all the time, I just listen to them through the earpiece speaker and there is an absolute need to be able to adjust that volume. Maybe this is a strategy to force people to buy earphones. In this case, it would be a morally very cheap strategy. That is the very basic function of the phone and with IOS 16 we lost it. I hope it is just a bug and it will be fixed very soon.