Reserve synchronous communication for what actually requires it.
Production is down. A customer is furious. Someone’s blocked and burning time. These are emergencies.
Everything else can wait.
Create one channel for genuine urgency. Keep it quiet. When something shows up there, people know it matters.
If you cry wolf by using the urgent channel for non-urgent things, you train people to ignore it. When real emergencies happen, no one responds.
Protect your emergency channel. Use it sparingly. When it lights up, everyone pays attention.