I tried KMail and Organizer for a few weeks, but they kept losing connection with Gmail. My calendar would get out of sync, and they only way to fix it was to reset the connection and redo all the appointments.
I’m sure it was user error, since I couldn’t figure it out after spending a couple hours on it, so I just dropped back to webmail and not leaving the mail tab open all day.
Kinda ironic that you are discussing the nonsense of “how things should work” on a federated service where you control the intermediaries you work with and through, which is, IMO, the way things should work.