Heat from power transfer is not the problem with current battery tech. We are already capable of delivering 350kW worth of power into EV batteries. The limiting factor is not the power cable delivering that power.

Thick cable, high voltage (900V typically) and everything is fairly manageable. Assuming we could consistently charge at that 350kW we could fully (0->100%) charge an 80kWh ev battery in 13 minutes. That's not slow.

The limiting factor is the battery chemistry, not the wire chemistry.