Green hydrogen only works when you have more energy than needed and you're 100% renewable electricity. You could have done that with nuclear power in the 60s in theory. But solar in abundance is the only likely route it will work.

Hydrogen will never be a viable fuel and will never save the world. It leaks like hell, has a low energy density so it needs to be either highly compressed or highly refrigerated to liquify it to be even usable for something that is moving, which needs a lot of energy and induces a lot of constraints.

Basically, everywhere where electricity is a meaningful solution, hydrogen is just outclassed. Which leaves heavy industries and maybe cargo ships. The rest must either electrify, or just go.