Garbled Playlist Audio

I just got a new PC with lots of horsepower (Win 11 Pro, i7-11800H, 32GB RAM, 1 TB SSD, NVIDIA GeForce RTX 3070 GPU) but with it comes a ton of audio issues when using ManyCam virtual Mic that I didnt have on the former PC. Now, whenever I play videos or audios in ManyCam taken over to Zoom via virtual cam and virtual mic - the audio is completely garbled with echo and feedback of the audio back into my mic. This never happened before.

Please Let me explain my Audio Chain and what I’ve discovered the problem to be.
Rodecaster Pro II is my audio interface and I use it as default input device and default speakers. It’s got independent Gain settings for each of my mics and it has independent manual mic mute buttons for each channel.
I feed the Rodecaster into ManyCam as audio playback device and also set it as the Microphone audio source.
So far so good. Many picks up my Rodecaster and sends my voice over to Zoom via Virtual Mic
The problem starts when I play videos in ManyCam. My Microphone picks up everything and sends a garbled echo filled mess back into zoom. But here’s the the thing. I mute my mic on the Rodecaster and so Many Cam does not pick up my voice. The Mic itself is muted - indeed - if I speak into the mic while it is muted on the Rodecaster, the VU meters on ManyCam register no sound. BUT despite the mic being muted, when playing video the VU Meter for the playlist is fully active and the Microphone VU Meter picks up all the sound of the playlist. The Mic Is Muted!
So It becomes apparent to me that there is a driver issue that I never had problem before. Something in ManyCam is mixing the MIC and The Playlist because the mic is muted and my voice is not being picked up by it.

I desperately need to find a solution to this. Anyone else experience this and find a fix.
As a temporary solution, I can mute the microphone in ManyCam but it should not be picking up system sounds or video sounds sound when it it muted on the Interface / soundboard. There’s a driver problem here.