Ethiopia may be another candidate for an ATL where a country breaks up into smaller states. Viable
language-based entities may form based on communities of Afar, Oromo, Somali, and Amhara speakers.

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Image source)
Ethiopia's
religious divides based on Ethiopian Orthodox Christianity, Protestant Christianity,
and Sunni Islam, similar to OTL Yugoslavia, may help for the basis for Ethiopia fragmenting into multiple nation-states.
Ethiopia's relatively recent conquests of non-Amharic speaking regions form the potential for a POD involving a Russian Civil War-style imperial collapse and the emergence of several nation-states (Poland, Ukraine, Baltic States, etc). Ethiopia is Africa's Austria-Hungary.

PODs:
1) A more disastrous 1961-1991
Eritrean War of Independence makes Haile Selassie's regime increasingly unpopular, and civil war breaks out in addition to the conflict in Eritrea.
2) Somali victory in the 1977-1978
Ogaden War results in Somali gaining the eastern, Somali-speaking region of Ethiopia. Somalia-backed rebels from other ethnic groups rebel against the
Derg military junta.
3) Eritrea gains independence before 1991, but the Derg takes power as OTL. Ogaden war goes as OTL. Ethiopian leader Mengistu Haile Marian launches a war of conquest against Eritrea or Djibouti to gain sea
access à la Iraq v. Kuwait. Then, a Gulf War analogue takes place against Mengistu Haile Marian's People's Democratic Republic of Ethiopia. The regime loses power in a death of a thousand cuts by various ethnic groups against the Amharic-dominated government . This would require a POD involving Eritrean independence happening earlier than OTL.
4) The OTL 1991 transitional government led by Meles Zenawi (Ethiopian PM 1995-2012) falls apart with a POD that removes Zenawi's leadership. The
Ethiopian People's Revolutionary Democratic Front (OTL present-day ruling coalition) fragments into its ethnic Oromo, Amhara, and Tigray regional parties. One or more of the parties may push for their regions's independence as a peaceful breakup in a czecho-slovak style velvet divorce. Alternatively, a more chaotic series of separatists conflicts against the politically dominant Tigre community results that is less of a break-up and more of an implosion.