Slack was a disaster for us when we last tried using it. Several people muted it for hours at a time, the only way to get someones attention was to call. By which point it was probably important enough to warrant a call.
Our theory is that for people to be able to focus on work for reasonable periods of time you need good async communication. And for that need good sync communication for where it's appropriate. We've been using whereby.com for video calls, much better than zoom. This is where we all checkin and Sam/Pat find out what the need to keep an eye on, and then they can start a thread on plum mail for the content they need to keep track of over time. One of the favourite features we have build from a manager side of things is the following. A manager can join a conversation, but then set the notification level to be only notified when a conversation is resolved, i.e. they find out the conclusion and can see the history if they want, but the aren't distracted by the discussion towards the conclusion