Hello,
Windows 11 gives the user the option to change its per-app sound output. Meaning, you can select different output sound devices for different apps. The system sounds are also considered an app in this case. You can manage the individual output sound devices per app from Settings >> System >> Sound >> Volume Mixer (Under Advanced settings). Here, expand “System sounds” and then you can select the output device to a different sound card from the drop-down menu.
We would like to add that in order to manage the output sound devices of other apps, the application(s) must be running so that the system can register them, and then you will be given the option to manage their output devices.
You can also refer to our other post that gives multiple ways to route your audio from individual apps to specific output devices/cards:
https://www.itechtics.com/route-audio-pc/