Connector? This is about wireless charging.

If you're worried about the wire to the charger itself, I'm sure they've thought of that if the charger is submersible. (Do any of those exist? I'm only finding a splash-resistant one.) And if the charger isn't submersible it'll be outside the bucket and the cable will be fine.

I do see some wireless charging waterproof battery banks. No cable needed for that.