>We can use one or all these solutions.

Wrong on saying we can use only one of them. Batteries and transmission are both a must. Because of the intermittent nature if we want to continue increasing renewable production we must have batteries. And if we want to do this in a remotely sensible way, we need transmission to move electricity from where it is most efficiently and economically generated to the cities where people are.

By the way, your hydro and heat reservoirs both are just non-traditional batteries.

And only charging EVs when there is excess power is a good way to kill off EVs. I know I would never buy one if that was the case because I don't plan on getting stuck somewhere because no charging was considered a valid option. Economic incentives about when to charge are already being done and are perfectly valid on the other hand.