Tigray and Amhara people accepted Christianity as their religion as early as the 4th Century, when Aksumites kings offically accepted christianinty and started using the cross as a symbol in their moneyas the following image shows.
Federalism should the future for Ethiopia. As some regions will have a stronger decision making opportunities on their population and region.
Afar, Somali, Southern region and also Oromo have benefited from Ethnic Federalism.
Amhara should support federalism. Tigray already supported Ethnic Federalim as TPLF has already initiated it.
However there should be some modification to the current Ethnic Federalim, specially to land given to Oromo and Somali, which does not correspond to historical evidence. Oromo is more around Arrusi. Amhara have more land : Bale Wollega etc. Tigray should also have more land.
I think we should re-arrange the current internal territory of Ethiopia based on historical evidence.

We have to be fair to all ethnic groups. Oromo will have territories they need and so will Somali people. But the current internal administrative map of Ethiopia is unacceptable.