The correct answer as of February 12, 2024 is NO.
There is currently NO option in Windows 11 to select ONE OR MORE preferred output devices and disable ALL others.
There is NO option to flat out disable audio routing via USB-C or via HDMI at a system level.
There is NO option to disable automatic switching of audio device when a new one is recognized. ANY newly connected device will come with a risk to start playing automatically, whether or not it was previously recognized and disabled.
The problem WILL NOT be resolved and people will keep having issues and posting this question until these fixes are implemented.