Staying with the classic app. I don’t even have the new app installed. I too would love to work with the new rules engine. I have some automations that would definitely benefit from the added flexibility present in the new engine.
I moved all of my automations, except my cameras, from webCore to smart lighting awhile back. I did get most everything to work pretty much as with webCore but had to use a ton of rules and virtual switches to do it. I was trying to see what I could get working if I were to move to a V2 hub with local processing.
Anyway, only my login is migrated. This also migrates the IDE. Until told to do so, I am going to only have installed the classic app to make sure that I don’t have any avoidable issues.