Merkuro apps are the new Mail, Contact, Calendar... for Plasma desktop. A huge effort is done to create them and provide new experience for users.

But in the backend they rely on is Akonadi server, which is the nightmare of any Plasma user, because that server with its apps (kmail, kontacts, knotes...) are stuck at no return point. Those apps will work at first, but after certain time they will surely break, and you will lose your precious data. It's like Akonadi needs a hard reset from time to time.

The main culprit of such disappointment is no other than Akonadi server itself, and how it was made the backend of its apps and packed with many plugins to a certain degree it became unstable and difficult to maintain.

The same error is done again for the new Merkuro apps and how they were fast tied to Akonadi to avoid rewriting connection plugins to online services.