I just wanted to add other storage challenges to your list, but upon googling for it, I had to learn that something called liquid organic hydrogen carrier exists:

"Hydrogen oil – LOHC – has two great advantages compared to compressed and liquid hydrogen:

The hydrogen is stored in oil, LOHC, and there is substantially less free hydrogen on board the ship, which reduces the risk. The hydrogen oil can be transported in conventional tanks, about the same way as for diesel today, and therefore has substantially lower transport costs than compressed and liquid hydrogen."

https://greenshippingprogramme.com/pilot/infrastructure-for-...