Right-clicking on the tray icon of the applet, the context menu contains the same option, "Instant Messaging Settings ..." twice. However each options behaves differently, as one is added by KTp and the other one is the default "applet settings" action. This is super-confusing and basically broken. Ideally the applet should use the Plasma-provided configuration (but that requires QML-based UI AFAIK?), or the actual option should be named differently.
Yup.
Thank you for the bug report. As this report hasn't seen any changes in 5 years or more, we ask if you can please confirm that the issue still persists. If this bug is no longer persisting or relevant please change the status to resolved.
Dear user, unfortunately Telepathy is no longer maintained. Please migrate to another solution, e.g. for Jabber a possibility is Kaidan, for Matrix a candidate is NeoChat.