You know, the back button works in Google Maps and does exactly what you might think it does: take you back to the state you were just in.

After you accidentally lost your route, you could have just used a built in feature of your browser to get yourself back to where you were.

EDIT: The rest of your post was entirely accurate. Google Maps is a slow, stuttery mess on literally every platform I've ever used it on recently. At least the back button works...