a) letting customers in other areas know that their data is backed up to another continent
b) asking the AI model of your choice to translate the following into PR-speak: "Because of the boneheaded data residency requirements in this country, all your data is gone, and we weren't able to do anything about it - here's an empty copy of a re-setup version of whatever infrastructure we provide, glhf setting up everything from scratch, hope you had backups"
For customers who use such a provider or operate primarily in that area: Restore from local backups, or tell whoever depended on you that everything is gone and if you really didn't have backups, probably close up shop.
Multi-cloud in the same country (if that exists in the country and is far enough apart) maybe.
me-south-1 is about 250 miles away from me-central-1, but that's not far enough in this instance. Given that, I think city level location information should be good enough.
250 miles is pretty good for weather or not specifically targeted destruction (wildfire / industrial explosions / arson), but it's clearly not enough if your data is in a building targeted in a regional war. Assuming datacenters remain targets in wartime, I think it's fair to assume if one datacenter in any particular country is attacked, all the rest of the datacenters in that country are likely to be attacked, too. In that case, offline storage (tapes and things) in inconspicuous locations might be the way.
(or an AWS Outpost thingy, assuming those things work even if the mothership is down)