My PinePhone makes and receives phone calls okay, but the volume on my end is very low. It's turned all the way up. It's much quieter than any other phone I've used. The ring volume is also very quiet. Is there a way to make it louder, or is it just a limitation of the PinePhone's hardware? I'm using an AT&T MVNO.

@KarolinaK I am having the exact same issue. Call volume and the overall volume of the phone is not loud. I can't hear it ring when it's in my pocket when I'm out in public. I can hear other people in a call, but just barely. My volume is turned all the way up.