iPhone XR audio going in and out?

I got my iPhone XR around 7 months ago. I haven’t had any type of damage to it and all of a sudden a few weeks ago, I started having audio issues with phone calls, “hey siri” and recording videos. For phone calls, the volume is low and almost inaudible if i’m in a public place (talking, cars, birds etc.) If i’m not in a quiet room or have my earphones in, it’s very hard to hear who i’m on the phone with. For videos, if I record videos the sound goes in and out/up and down. I also have to have earphones in for the sound to work properly while recording. The sound works perfectly fine on everything else (youtube, instagram, voice memos, playing music, etc)whether I have earphones in or not. it’s just my phone calls and recording videos. One thing I have also noticed is that saying “hey siri” no longer activates her, i tried turning it off and back on to reprogram my voice, but it keep saying it couldn’t understand me.