zoom audio issues/black magic web presenter

hello I have a setup that consists of:
Yamaha Mixer
Windows computer
zoom software
Black magic switcher
black magic web presenter
I have a few inputs into the switcher, I have a PTZ camera, as well as the computer HDMI

into the mixer I have the AUDIO out of the PC into the mixer, so I can play audio / video from the PC to an SDI out solution to different displays in a large facility. All that works fine.

the newer part of this solution is the black magic web presenter. I have this connected up I believe properly

I have the switcher output going to the web presenter using SDI
i have the web presenter USB going to the computer as USB input
zoom see's the camera properly

When I send any audio from other sources IE a mic off the mixer, the zoom audience hears this just fine. audio on site is also ok.

When I play a VIDEO from the PC the audience over zoom can see the video just fine, the audio quality is less than desirable.

I have tried adjusting nearly every setting on the mixer, and no success. I can't clean up the sound.

the quality is really bad.

However today I tried to use the zoom SHARE SCREEN feature, and I shared the audio and video and it sounded GREAT.

any ideas / work around to making the sound better when using the web presenter?

share the screen using zoom has its own challenges, so would prefer to use the black magic alone.