So, I'm not entirely sure I'll convince my organization to move to Zulip from Slack, but I'm gathering ammo, and am comparing integrations. Here's one missing that we use:

https://help.clickup.com/hc/en-us/articles/6304922742295-Slack-integration-overview

UPD 2026: I don't work at that company any more, and don't personally care about this integration any more. Issue is still kept open as something to track the gap with Slack