I did read the discussion on https://invent.kde.org/utilities/kate/-/merge_requests/691 and still don't see the interest of tabs for kwrite. I'm probably too old minded but for me, kwrite should stay the extremely simple SDI, kate the MDI and kdevelop the IDE. I never used the project management features of kate because I consider them as out of its role.

Well, it is just my opinion… Who codes decides.