Looking at that picture, move the Arc to the front of the cabinet

Someone used to make a mount for the PLAYBAR that mounted it on the bottom of the TV, I’d be looking for something like that, if it exists. 

Something like this, which took 5 seconds to find using Google. 
 

I put my Arc at the front edge of my table and moved the TV to the rear. It lets me pivot it a fair amount without the TV impacting the Arc.

If your mount can take the additional weight mounting the Arc to it also would work.

I went the way I did as I didn’t want to fool with trying to figure out TruePlay with a movable speaker.