Deal with the dilemma. Here are some options.
1, Let the parliament vote whether to release Tigray or keep it as a local entity. (Welqait situation need to be considered.)
2. Use human waves to deal with the agames. In the long run, Ethiopia is guaranteed to win.
3. Take war to Tigray. Subdue Tigray with human wave regiments at Ethio's convenience.
4. Insert Amhara guerilla fighters in Tigray.
Remember conventional war will not win it. They are suicidal. You need to fight the same.