> It's well known that hydrogen makes most (possibly all) metals become brittle over time.

It's not "well known." In fact, this is bullshit. Only some metals have this problem. Even then there are ways of preventing the problem via coatings and the like. Nor is it even necessary, as geological formations can be used to store hydrogen in the same way we store natural gas.

You are simply reading too much pro-BEV propaganda. These are solved or are easily solvable problems.