I think I have used this before, but in my current scenario it may not work, as the current (classic) app is using google sheets and once I migrate I want to get rid of googlesheets due to the syncs.
Also when you do this, I assume the formulas are NOT copied across and you have to recreate the formulas again ?
The New App from Data option only applies if you are converting a Classic App to a New App. That is completely separate from Legacy Plans and New Plans.