Where are Messages now stored when you enable iCloud sync? There is a new cloud messages option for iCloud users. After Updating to macOS 10.13.5 and iOS 11.4 and checked all the boxes to get Message to sync across all devices and computers.

When you do so, you are alerted that your Keep Messages setting on your phone/pad has been changed to Forever.

Anyone know where those Messages can be found/accessed???
You scroll above the top of the message history. A spinning wheel will show while messages are downloaded from iCloud. You can repeat this to show more messages. There is not a separate view for Messages in iCloud — it's integrated with the Messages app here.