iPhone 12 Pro Max speaker issues

I had an iPhone 12 Pro Max that was about 6 months old and I got me a 13 pro max and gave the 12 pro max to my wife( both are fully paid off) my wife has taken care of the 12 pro max yet there is a unusual issue going on. The volume in the speaker is so low that you can’t hardly hear a person talking on the other end. You can put it on speaker and hear but still have to hold phone up to ear to hear clearly what is being said. Have looked on YouTube and done all quick fixes I have read about but to no effect as of yet. Could someone PLEASE enlighten me on what could be causing this? Thanks Apple community