I have not.
Vertical chess

I agree with you. The vertical rectangular boards distort the diagonals.
I’ve seen this type of vertical board in YouTube videos.
https://www.chessusa.com/product/64-200.html?gclid=EAIaIQobChMInv_SkZKF4gIVwYqzCh2ekQDOEAQYEyABEgLAO_D_BwE
I like the idea of some of these vertical/wall mounted chess sets I’ve seen, I think it’s kind of a cool/functional/artsy idea. However they all seem to have rectangular boards rather than squares, which I find odd and disorienting. Am I the only one? Does anyone have one, and do you like it? Have you seen square ones anywhere?