THX Spatial Audio on Blackshark V2 help.

Hi, quick question here again: Do I have to set the THX Spatial Audio as Standard-output-device or not? The guide of the Razer Blackshark V2 says that I have to choose the usb-sound-card, but razer synapse 3 itself gives me an alert that I should put THX as standard. What should I do? Also, should I switch between THX and Stereo when I game and when I as example watch videos or should I just let the soundcard chosen and THX will automatically activate when playing a thx-compatible-game? Thanks for your help fr fr