Why is my iPhone volume changing on its own

The volume level of the iphone speaker is changing on its own, without my control. This happens during a phone call, streaming music, on speaker phone etc. The sound level will suddenly drop without my control. I've contacted apple support and their recommendation is to update software. Which did nothing to resolve the issue. Then, searching the web i realized a lot of people have this issue too. In settings, i've toggled OFF the 'change with buttons' feature and the 'attention aware' feature. Still no resolve. Anyone have a suggestion to eliminate this glitch. Iphone 12 ios 15.6.1.

The phone worked without issue for almost 2 years. Now this. Thanks apple for trying to help me with all these useless settings i dont want!! please stop spying on me. please stop messing w my phone.