"Many, many, many" isssues indeed. Like being compatible with existing EVS and ICE vehicles, and keeping aeroplanes in the air, and being compatible with all fossil fuels infrastructure, all with minimal adjustments. Good fuel systems Engineers know all of this, ask Rolls Royce, ZeroAvia, Airbus, Cobham. I've worked for most of them, Systems Engineering.
Many more issues like filtrating and circulating water, cleaning the air, and even creating food. I guess you don't know much about Solein - food from sunlight independently of the conventional food chain, with the potential to remove some of our load from the latter.
The most commone and popular hydrogen fuel cells and electrolysers now contain only polymer membranes. So like the disinformation generated also about solar panels, it is not true to claim there are any rare or toxic materials in them. Where did you get this misinformation?
Many more issues like actually being perfect for any solar powered household or community to pump their excess energy into a local tank, so as to ensure their own energy security independently of the grid, and sell their excess to passing hydrogen powered transportation to gain revenue from their solar power, to even scale up their / our installations to make yet more revenue, replacing the panels in their installations one by one, infinitely extending the lifetimes of all of them, nothing asked in return from the sun, all for free, but best of all, the opposite effect of heating the Earth by continued extraction of Energy from it, the more solar power we use the better, which brings us to your final argument - efficiency. Who cares about efficiency, when what matters from solar power is that any of it is put to use at all, every Joule converted to something other than heat, is a Joule subtracted from the heating effect on Earth.
So even 50% efficient use of solar is a 70% improvement over 80% efficient use of any energy extracted from Earth, in terms of the heating effect on Earth.
Remember the target was "Net zero"?
The scenario I just described to you is much better than net zero, and best of all, the more using it the better.
So you should go back to whatever research you have been doing and revise it because it is wrong, dude, very, very, very wrong, in fact existentially wrong.
Where did you train as an Engineer?
Or did you just train as a salesman, for maybe the grid?
Grids are finished. I can tell you this with certainty, with even numerical data backed proof, they are a dead duck, nature is winding them down, as we speak, no-one needs them any more.
Here is some proof:
