Abiy has to restore the territorial integrity of Tigray & restore TPLF before Tigray allows Shabia tanks enter Tigray!
Obviously Isaias plan is to use Tigray as a buffer zone by positioning its army to Tigray locating them on the Amhara Tigray border. If that happens Abiy should be ready to face Eritrea, Amhara & Tigray army together. By pushing TPLF to the corner, Abiy is risking losing strategic alliance partners of the Oromo people which are Tigray & TPLF. The risks of angering Demeke Zewidu are much lesser to angering Tigray & TPLF.