My PT had me do something akin to a bicycle motion with one leg, dorsiflexion on the upward movement then plantarflexion on the downswing. They had me do calf stretches in the pool too. I was told to be careful of overstretching because in the pool you don't feel it the same because the temp difference. When I was strong enough I started walking in there.
On land, making the alphabet is good, picking up marbles with your toes and transferring to a cup, everting and inverting, ankle circles, towel pulls and lots of cool stuff you can do with bands that you can find videos of on YouTube. The "foot shortening" exercise works all the intrinsic muscles and requires only the foot to do.
Let us know your surgery day or if you cancel

. We'll be sending lots of healing vibes.