2020 4Runner bt question

Dumb question but also I can also say I haven’t dove into it really either. My wife has her phone paired and when she gets an incoming call and talks the voice ( from the other end ) is only coming out of the right front speaker ( I think ). So she has to turn it up super loud to hear the other person. A lot of times she says she just switches to handset. Is there a way to change the stage or adjust the volume? Honestly I haven’t had time to look at the radio/manual. She has an iPhone. Don’t know if the phone can use it’s volume in addition to the radio to increase volume or if the radio is primary volume control.
My ‘15 Tacoma has the bt come out front stage on phone calls so it’s clear.
Thanks in advance!
David