iCloud Keychain not turning on or syncing across all devices

I recently got a new MacBookAir (Monterey 12.2.1) and couldn't get the Keychain to select on the System Preferences/Apple ID/iCloud panel. So I began looking online for answers and came across:

Keychain passwords not syncing between de… - Apple Community

An answer to that article recommended the following:

“If you want to sync iCloud Keychain with other devices

Make sure that your new device has the latest version of iOS and the latest version of macOS.

 Then, make sure that your device is on a Wi-Fi or cellular network. If the connection appears strong, try these steps:

1. Turn off iCloud Keychain on all devices.
2. Turn on iCloud Keychain on the device that has the most up-to-date keychain items.
3. Turn on iCloud Keychain on your other devices. They will be updated with your new iCloud Keychain.”

Upon following the above instructions, Keychain can now no longer be turned back on on any of my devices (MacBookAir, iMac BigSur 11.6, iPhone 8 iOS 14.4.2, iPad Air 2 iOS 14.8.1).

However, Keychain is still working and is filling in passwords/forms and displaying all my sites and passwords. It's the syncing over iCloud that is broken and I'm hoping to fix this without losing all my password data.

Any help or ideas would be much appreciated!

Thanks, Len