Hi, my name is Neil, I'm an independent adviser and a Windows 10 user like you.
Sorry you've not been able to find how to turn off spatial sound setting.
You can turn spatial sound on or off from the sound icon in your notification area near your clock.
Plug in your headphones/headset.
Right-click your speaker icon, hover over Spatial Sound, and select “Windows Sonic for Headphones” to enable it or select “Off” to disable it.
I hope this answers your question.