I can’t remember the details, but I don’t think ICE itself will be banned, it’s that vehicles have to be zero-emission (of carbon). If someone develops a reliable ICE technology that is 100% emission free and always would be – for example, a petrol burning car that captured 100% of it’s carbon still wouldn’t be allowed because just as with old 350z’s and Celica’s where some drivers removed their catalytic converters to improve performance (they had a “quick fit” mechanism to slot the CC back in at MOT time), those same drivers would just unplug the capturing mechanism (and of course, petrol via oil still needs to be extracted from the ground).
Hydrogen ICE would certainly be possible but H2 is highly corrosive. Like you said there are difficulties with storage and processing, but wait! H2 can be generated easily with electrolysis (from solar panels), and some scientists have had success in bioengineering algae to produce H2. We already sell LPG on forecourts, the engineering for which might not be too dissimilar to that required to deliver H2.
But I still think IF H2 has a future as a fuel it would be via fuel cells, not ICE. Riversimple (in the UK) have developed a hydrogen fuel cell vehicle they plan on selling to the public soon. I think it’s rather funky. It wouldn’t meet my needs but I’d certainly at least consider one over an EV if it did. I’d definitely like to take one for a test drive.