Notes null

Force close the app and then force restart the device.

Force restart by -

On an iPhone 8 or later: Press and quickly release the Volume Up button. Press and quickly release the Volume Down button. Then, press and hold the Side button until you see the Apple logo.

I also have had this same issue since the release of iOS 12. The issue does not occur on my mac because it hasn't changed OS, so it's not an account issue.

I have also signed in and out of iCloud on my phone as well as restored my phone and used the most recent backup. Issue persists.

I'm trying to avoid restoring and setting up as new.

The problem still persists after applying the suggested solution.

Make a full backup, restore to factory settings and set up as new.