Russia is an important exporter of fertilizer, fuel and food. In contrast, most of the third world imports these things.

Sanctions imposed by the West do not (and cannot without a naval blockade of Russia, which no one in the West is crazy enough to advocate for) prevent the third world from continuing to import these Russian exports, but they introduce significant friction on these transactions.

Much of the third world does extensive business with Russia and rely on Russia for access to advances technologies. For example, Russia is helping Bangladesh build its first nuclear power plant: https://world-nuclear-news.org/Articles/Rooppur-Bangladesh-p...

I mean, Ukraine and Russia both export a lot of grain, so the war has definitely impacted a bunch of poorer countries.