This does seem to be the common way to do it, unfortunately.
I really feel like Esri needs to find some way to set up a test environment for these forms that doesn't just require creating a duplicate, it feels like there should be some way to do this. It is possible to have different versions of a form out there, as you can not Require update to the latest version of this survey but there's no way to prevent users from being prompted for an update until it's ready to be pushed. I feel like this needs to be added.
If there's a concern around different schema on a feature layer when adding new fields or such, I personally feel as though this isn't a concern because the user won't see new fields until you get them to anyways. Or my other thought you be using a hosted feature layer view, there's already a _results view that gets created when you share results, could there be a _test view to store results submitted as a test? Maybe have a field in the base layer marking them as such so it doesn't get included in other steps or analysis?
