Sound alerts far too quiet

I have the iPhone 13 Pro Max and seem to have the problem lots of people are talking about…

the alert sounds like text or msn mail sent mail and even close phone are all barely audible.

if we follow the instructions to just use the slider in the sounds the ringtone goes really load which is fine and that’s with the button for using the side vol control switched off.

but however the alert sounds do not go up to anything like the volume that they did on my earlier phones…

I’ve tried numerous fixes from forums turning stuff on and off but it all boils down to 1 volume control that turns up the ring tone but barely if at all increases the alerts.

please sort this out.