Khadafi,
I concur on all points. It is a slow decline or death that needs to be accelerated in order for the Horn to find lasting peace. The TPLF might be out of the picture, but as you said they did implant the seeds of destruction. Amhara wants to supplement Tigray as the new lords, but with rising of ethnonationalism and the revival of cultural and linguistic rights of every nation, it is hard for anybody to take Ethiopia back to the old 'good' days.
It is worth noting the Oromos that are actively fighting the state were the Christain Orthodox in Western Oromia. Amharas tried to create a narrative of Muslim extremists vs poor Christian victims. But it did not get any traction since the majority of Muslim Oromos are in the east and south.