You forgot the most important option of all: closing the window. Unless your occupation precludes constant communication (like emergency services or such), the

You forgot the most important option of all: closing the window. Unless your occupation precludes constant communication (like emergency services or such), then the expectation should be that you are generally contactable, not constantly interruptible. And if you can't close Slack without fear of repercussions then the problem lies with your company, not Slack.