EV charging around Bordeaux is plentiful and cheap. Any recent EV hire car will have adequate range. Take pics of the car from every angle when you pick it up and avoid a drop off time when there is nobody around to check it over with you.
Arcachon beach or Cap Ferret are good spots for a swim if the ocean is wild. If you do swim the ocean read up how to swim out of a baïne and try to avoid getting into one in the first place. Open water swimming in lakes if the ocean is really too wild, Sanguinet is my favourite with crystal clear water. On the way you can stop off at the Dune de Pila which is a pleasant hike beyond the point the tourists often stop.
Hire some bikes and cycle the railway trails to Lacanau or Sauveterre.
Go (window) shopping along Rue Ste Catherine, drop into the tourist office and ask them which vinyards do a good tour
Take the train to St Jean de Luz, walk the coast to Hendaye and walk the Compostelle route back, or take the bus. Do the Rhune walk if you have a car and can park somewhere suitable, we park in Sare and access via the GR10
The “peregrinos alpinistas” walk over Jaïzkibel and taking the little ferry at Pasaia from Hendaye to St Sebastien is good, Topo train back to Hendaye. Careful, you may end up walking all the way to Compostelle.
I any of these are of interest I can add detail.