Another neat trick I've picked up on from other people use is to use DND mode on Slack when you're focusing. That way if it's actually critical to get a hold of you in real time (but not so critical that it warrants a page) there's an option to do that.
People are surprisingly respectful of it, and unlike just going dark it signals to people that you're available if need be but focused on something.
People are surprisingly respectful of it, and unlike just going dark it signals to people that you're available if need be but focused on something.