Contact Samsung support via Members app
@spritestar: What happens when you tap on 'Speaker' while on a call. Can you hear that caller, but they can't hear you, or is completely unresponsive? In the meantime, please head to the Samsung Members app > Press and hold on the app icon > Diagnostics > Speaker, and follow the on screen instructions. Does this test flag any issues? Similarly, if the caller is unable to hear you while you're on speaker, tap on 'Mic' and run through the test. Let me know how you get on.
Have you tried, Device care - Diagnostics - Speaker? The test test both speakers the in-call and the media speaker.
If you do the test, can you hear both speakers?
Did you check permissions?