“I am very busy and have my work day planned to work efficiently, so I won’t be handling your request immediately. This means things can slip through cracks if there is no ticked describing the task created - create one if what you are asking for is of any importance.”
Followed by not doing anything that doesn’t have a ticket and didn’t come directly from people you report to.
Also I have notifications disabled and only check slack between tasks or if I take a breather from a task - on average 4-5 times a day. I also check email as the first and last thing in a workday only