Really I think you’re gonna have to have some parameters like rural vs. city infrastructure, electrification, access to (clean) water, and possibly even solar and wind efficiency in there, to account for a lot of poorer countries in this world.
In many poor places near the equator, for instance, it’d make quite a lot of sense to fund solar ovens and subsidize solar panels. Or if electrification is poor, you could hand out gravity lights (that’s efficient LEDs driven by a weight which slowly falls, like old grandfather style clocks) etc.
- Low cost infrastructure which (other than solar panels) barely makes sense in a developed nation where even the most remote of places has more or less stable electricity, clean water, and at least reasonable cell service (ok that last one is not rarely a stretch 
), but for rural developing nations it can make a huge impact.
For instance, that gravity light idea? Seems silly perhaps. But it means children can actually work on their homework after sun down without expensive (because non-reusable), hazardous candles, so it can have quite a solid impact on education for very, very little extra cost.
Granted, perhaps such things are better left for an expansion of sorts. But that kind of thing is what I mean when I say the system needs to be much more in-depth to accommodate fairly arbitrary countries on this planet today or even in the very near past and future. (Like, I’m talking a couple decades at most here. Things can change rather quickly)
Effects of colonialism can also not be understated. For instance, quite a few African nations got pretty solid railway connections during peak colonization. If your highest priority is to extract and export as many resources from rich mines as quickly as you possibly can. They are, on the other hand, rather poor at connecting actual population centers. And expanding that kind of thing is really expensive.