Step 1 - turn off all notifications, noise and badges. This will allow you to not be disturbed by interruptions.

Step 2 - if step 1 doesn’t work then shut slack down while working. Being reachable 100% of the time is insane. And the barrier for bugging is super low with Slack.

Step 3 - if 2,3 don’t work then use something like dispatch.do to prioritize all the junk and filter out all the noise.

Step 4 - it’s a you problem. Find a new job or seek professional help.