@mighty talon So I run a similar setup, just a bit flipped in how I handle audio.
In my case, my gaming PC sends all its audio over to my streaming PC, which I treat like my audio mixer. My headset is plugged into the streaming PC, so I hear everything—game audio, Spotify, alerts, Discord—all in one place with full control.
Ideally, your gaming PC should only be outputting your game audio, while everything else (Spotify, alerts, Discord, etc.) runs on the streaming PC.
You can try sending audio back from the streaming PC to your gaming PC/headset, but it gets messy. Wave Cast basically outputs a single mixed signal, so everything ends up combined instead of staying on separate channels.
Unless you’re using something that can specifically route audio to separate outputs (like forcing individual apps down their own audio lines), you’re usually just pulling in all audio—or one selected app—without much control between sources.
That’s why I recommend handling everything from the streaming PC. In my setup, I’m using a BEACN mixer, which lets me control exactly what I hear versus what goes to OBS. It gives you much better control over your audio and what your audience actually hears.
At the end of the day, you can set it up however you want—this is just the simplest and most reliable way I’ve found.
Small extra note: you can also send your mic from the streaming PC back to the gaming PC as an input. That way, games on the gaming PC (like Squad, Call of Duty, etc.) still pick up your voice for in-game chat. It keeps everything clean while still letting you communicate in-game without issues.