I found the sweet spot on belt tension.
The screws you want to adjust are the 3 screws that hold the dual idler pulley (right where the Y-axis rails end).
Important: Do not loosen them more than a half turn. If they’re backed off more than barely snug, they can vibrate loose over time.
I also learned the belt needs to stay fairly tight. If you loosen it too much trying to kill VFA, you’ll just trade it for ringing/echoing on corners.
The key when following the wiki method is to move the toolhead in big square movements (full left-to-right, front-to-back, front to right, etc.) do not move diagonally. That seems to help the tensioner settle properly.
This small adjustment made a big difference for me. I hope it does the same for you!