Recovery is not doing nothing. It is doing the right things at the right intensity so the body can adapt to the training stimulus you've already given it. More training is not always better: the adaptation happens during rest, not during the session.
On non-training days: light movement such as walking, swimming, or easy cycling, sleep prioritisation, and adequate protein intake. For members doing four or more sessions per week, we also prescribe targeted mobility work on recovery days, not to add training volume, but to maintain the range of motion under load.