Galbeedi,
A Somali has no future in Ethiopia and Muslims will not be given authority over historically Christian land. Any Ethiopian state has been and will always be hostile to Somalis.
You are right Tigray does not have the capacity to march to Addis by itself and take over the reins of the state. To his credit, Abiy has put the West in an awkward position, they have a choice between siding with him or watching the disintegrations. Siding with Abiy means there is no one doing their dirty work in the region, in other words, there is no Zenawi, and not siding with him will certainly lead to some sort of confederation with a weak central government, and a strong periphery that will dedicate the center, or simply outright secession. Tigray and in effect other regions will not settle for a very centralized state.
If this conflict showed anything, it is that no one is in a position to fully realize their goals. Ethiopia might turn out to be like Bosnia, an unhappy between people that hate each other.