My MG ZS EV howls like a banshee when reversing down our moderately sloped driveway. If the front brakes are wet, it doesn't do it.
Someone said back down the driveway in neutral. I saw no reason whatsoever for this to work, but I tried it and it works really well (not 100%, perhaps 98%). So for me, I get used to doing that, and it's just another MG niggle. Mine is a Mark 1 ZS; the Mark 2s seem to be a fair bit more refined.
In my case, the "proper" solution is to use the friction brakes more, but I find that to be less effective, and for me it goes against the grain to "waste" brake pad material.
I doubt that driving over speed bumps in neutral would work or be particularly practical, but in some extreme circumstances it might be worth a try.