All Notes disappeared after iCloud update
all notes disappeared after the adoption of new iCloud regulations
[Re-Titled by Moderator]
iPhone 12 mini, iOS 17
Try this
Open the Settings app.
Tap on your name at the top (aka your Apple Account settings).
Tap on iCloud.
Tap on Notes.
Turn on "Sync this iPhone" (green = on). If it is already on, turn it off and on again.
In the Notes app, wait several minutes for your notes to be restored from iCloud.