With my previous hearing aid I noticed that visiting a wide variety of web sites would cause a change in the amplification of environmental noise. I always assumed it was doing something with Bluetooth, and probably not for a good reason. This is with an iPhone 13 and one Kirkland/phonak hearing aid.
I haven’t noticed this recently, but I also now have two newer Phonak hearing aids and a few iOS updates have happened. Maybe the silent Bluetooth shenanigans are less disruptive to my new aids or the programming is different. Surely shenanigans continue.