Undo on ctrl z is not too bad if you have made a mistake. But the scenario here is different.
I guess what you really want is to do is flip through a range of pre-sets without having to go back each time. Like a sort of 'browse' mode.
I don't know I'd LR has that. So it might be worth requesting it if you can show your scenario to Adobe.
Having used systems with dedicated keys for OK, Cancel, Undo, Forward, Backward etc. Where you get used to working really quickly, it's strange that PCs have never caught up.
As a workaround, until things get better, you might like to define a mouse gesture using a gesture manager. I use them for: swipe right = forward , swipe left = back/undo and down-then-right = close window. I use 'easystroke', but there are plenty of others for all the OSs. And some have them built in.