alternately create a new only blackhole one, use that is input in if needed a second audio module? Then set sound control panel to only blackhole and voila, no more system audio. Not ideal though as you have to switch it back after being done to get anything out of the built-in sound out
blackhole is free. it has been working great for me since I first installed it while I was still on Big Sur. it has continued working on the latest version of Ventura. and as dialabrain has stated, there is no "premium" version.