Tplf only was able to take power in 1991 because everyone supported them, that is not the case today. Tplf did not march through Oromo regions and defeat ENDF, who told you that? They havent even step foot inside the Oromo region. They’ve been defeated in Afar region and are making advances in the Amhara region yes, but they haven’t been able to gain access to the Sudan corridor(their goal), nor have they stopped the blockade on the Tigray region. You are also not considering the fact that they will be spread thin this time around, if everyone from Amhara, Oromo, Afar, etc region is against them then they won’t have the resources to stop them all.
They were majority of EDRF as well with a minority of Amahar. OLA was small and weak like WSLF. TPLF had 100k members, EPLF (Eritrea) had 80k fighters they were the principle force that entered Addis Ababa and captured Eritrea. OPOD were useless movement the TPLF created from Oromo prisoners of war they captured.