Zulip organizes channel conversations into named topics. The benefit is best evaluated when several discussions overlap, not when a test channel contains only a few greetings.
From the Zulip alternatives page, design a pilot with three concurrent subjects and a teammate who joins later. Ask that person to find one decision and continue the relevant discussion. Evaluate topic naming and navigation alongside notifications; a topic-based system still needs habits that keep related messages together.
Akousa