What's the difference between "Reset from cloud" and just deleting things?
Completely different. "Reset from cloud" changes nothing on the cloud or device — it only re-syncs this app's view to match the cloud, discarding local edits that hadn't saved yet. "Delete" actually removes a to-do from the app and your Supernote. If you're worried your screen looks wrong but don't want to lose anything, "Reset from cloud" is the safe choice.