How we stack our equipment impacts sound quality. That's one of the difficulties of separates.
With an integrated or a receiver, we give up the rewards of choice enjoyed with separates. In exchange, we get a unit whose interaction and proximity issues have already been dealt with by the designer.
I have always advocated separating units by a reasonable distance. Even a few inches matter when it comes to EMI whose radiation emissions decrease by the square of the distance.
There are numerous ways to put space between components: tall footers, racks, isolation bases, arranging differently. Each has its merits and problems.
I think the important takeaway to this discussion is that distance between units matters.
As Claude Debussy is thought to have said, "It's the space between the notes that matters."