I hear you, was gonna put Ethiopia but tbh I know even less about what's going on there.
Indeed there are more pressing issues, I don't know if it's in this thread or another that I said that in THEORY I'm for opening a debate about borders, but def not in practice in the current situation because all those elements you pointed exist and cause enough issues as it is, and the state has to be strong enough in all its aspects to allow a serene discussion about borders to happen. Far from the case anywhere in Africa imo.
I see what you mean by those issues not benig tied to ethnic conflicts, but sometimes they are. In CAR the North and Eastern regions are even more underdevelopped than the others, and the state has never even tried to invest in them. Part of it is accessibility, but part of it is indeed the fact that those regions are inhabited by other groups than the ones in the West and the South. So end up with a link between no infrastructure and different groups. Those same regions are close to Chad and Sudan, and the groups living in those regions are mostly (not all) Muslim, so now you have a link between underdevelopment (by the country's own standard), different ethnicities, religion, and foreign meddling. That's exactly the mix that lead to the whole Séléka thing a couple years back,a nd it has been brewing for decades. Two things out of four (relative underdevelopment, and foreign influence) could've been avoided if the central power had cared less about making their groups eat good and had opened up to groups from that region. So yes it's not directly related, but sometimes the reason one region has shoddy infrastructure or receives less help in period of droughts for example is precisely because of underlying ethnic divisions. Not saying it's the alpha and the omega of all things African (because it's not), but it can play a role even where one might not expect it.
I agree tribalism is used too often to explain everything in the West, it avoids asking more macro questions (and questionning foreign meddling) and also well just applying normal frameworks (historical, political, sociological, cultural, geographical) to Africa, those very frameworks used everywhere to explain any conflict. I guess it's a form of keeping Africa "exotic". It's slowly changing in Europe though (well at least in France it is), somehow one of the "positive" byproducts of the so-called "war on terrorism" which is worldwide, so you have to apply the same frame of thought to Africa.
Not sure if the last paragraph is clear