Crossing one task off the list brings more peace than an hour of thinking about the whole list.

Thinking about a list keeps every item open at once, which is why an hour of planning can leave you tired and no further forward. Finishing one thing closes a loop, and a closed loop stops asking for attention. The calm is not really about the list being shorter. It comes from having one less process running in your head.

Pick the smallest item and do it now, even if it is not the important one. Send the message, book the appointment, wash the one pan. Momentum is much easier to steer than a standing start.