Iphone 6s - weird sound during phone calls

Last week I realized that something is up with my phone. When I make a phone call, the sound of the dialing (that beeping sound) is pretty high-pitched and disturbing. The whole phonecall sounds this way, the sounds sounds to be far away from me and also high-pitched. I started to check the phone, while i listening to the conco through my earpods, there is no problem at all. Listening the music/videos/the way they sound is also flawless.. Another issue connected to this is when i make a video with the selfie camera, i can hear some disturbing crackling sound in the background. What makes it even more weird is that when i use 3rd party apps like instagram or snapchat and I try making a video with the front camera through these apps, the sound of the video is good, i cant hear that weird static, crackling sound. I dont know whether my microphone is just dirty, but im sure that it cannot be connected to water, it never touched my phone, maybe just the rain but i dont usually use it when it rains. I tried hard reset, updated to the ios 13.1.2 from ios 13.1, i recovered my phone, tried to clean the microphone but i dont want to hurt it, so i stopped doing that. But no change at all.