Arcanum four is the most work-driven of the comfort zones. A person like this recovers not on holiday but in the work itself: in a task, in craft, in becoming better than they were last year.
They need reasons to grow — new fields, training, a setting where there is someone to learn from. They always have more plans than time, and some of them stay unrealised; that is the normal mode of operation, not a failure.
The main mistake the people around them make is trying to "spare" them by sitting them down at home. Without work, arcanum four goes out quickly and painfully, and no amount of leisure replaces it.
Rest is needed here as much as by anyone — it is just that rest, for this person, means a change of task rather than the absence of one.