The second (third?) most recent Sam Harris podcast episode with Yuval Noah Harari discusses this. We normally talk about UBI in the context of one country, but like you said, third world countries will suffer the most.

Automation killing basic factory jobs will have a much larger effect outside of first world countries, and unfortunately there's no real way to address that disparity from the context of policy in any one country.

Realistically, we know how the First World countries are going to solve it, because many of them are already in the process of implementing that solution. They'll dump some token amount of humanitarian aid to relieve their conscience, and meanwhile set up electrified razor wire fences with automated turrets and drones at their borders. They're not going to share as much as would be necessary to implement something like UBI worldwide, even at local levels of "subsistence wage".