Notes no longer syncing

As of march 28th my Notes have stopped syncing across my Mac, iPad, and iPhone. I have tried the obvious...

Logged out and back in to my iCloud account on all three devices.

Shut down and restarted.

Made sure in system settings on all three devices that notes are saved to my iCloud account instead of just the device.

Made sure "Sync this device" is on on each device.

Made sure there is plenty of storage on devices, as well as plenty of storage in the iCloud account (roughly half full).

Tried adding a new note to each of these devices, and given plenty of time with the apps open for them to sync (hours - then tried the restart again after that didn't work).

Any other suggestions?

Thanks!