Super quiet notifications over bluetooth speaker

Hi,

I've been having this annoying problem for some months now, when my iphone 12 pro is connected to any bluetooth speaker, the notifications sound very low, they are hardly heard. And the same happens with my ipad. I have tested on various speakers (JBL, Sony) the same thing always happens.

I thought that changing the device type on the letter "i" in the bluetooth preferences was going to do something but nothing happens. I keep missing notifications whenever I'm listening to music with a speaker.

My devices are on IOS 14.4.2

Any suggestion?