Stop allowing every notification to become a temporary priority.

A notification is somebody else’s item arriving in your day with an implied claim on it. Treating each one as urgent means your priorities are being set continuously by whoever happens to be messaging, and your own work is what fills the gaps. The default arrangement hands over the steering.

Turn off everything that is not genuinely time-critical, and check the rest on your own schedule. Decide when you look rather than being told. Most of what seemed urgent turns out to have been fine waiting.