Knowing how to be bored without a screen is a skill. Practice it in lines.

Tolerance for an empty few minutes is trainable, and for most people it has quietly dropped, because every gap is now fillable in under a second. The cost shows up later as trouble sitting with your own thoughts long enough to have one worth keeping. Ideas tend to arrive in the unfilled parts of a day, and the unfilled parts have mostly been paved over.

Pick one place you always reach for the phone: the queue, the bus, waiting for a lift. Keep it pocketed there and let the time be dull. It is uncomfortable for about a week and then stops feeling like anything.