iPhone microphone muffled

When I’m calling (or getting called) my microphone sound is very low on speaker. When it is not on speaker everything is completely fine. I tried to see what the problem was, and this is what I tried:

• cleaning the microphone
• filming a video on both sides, but the sound is normal in that
• using the recorder app. Here the sound is very muffled as well.
• restarting, updating to IOS 17 etc.

The microphone is not completely dead, but it just sounds like I’m really far away.

[Re-Titled by Moderator]