Did Imam Ghazali advocate for one Caliph (Imam) during his time?

In his book Al-Muztazhiri, Ghazali writes a refutation of the Fatimids. They were a group Ghazali argued who denied the literal meanings in the Qur'an e.g. like heaven and hell being real and many Islamic legal rulings. This group had taken over the Egyptian province of the Abbassid Caliphate declaring their own autonomous state. Ghazali makes the following points: 1. Caliph Mustazhir is 'the leader of the Ummah' and 'Amir ul Mumineen' (leader of the believers), 'the true Imam' and 'the Imam of our time' - not 'a true Imam', or 'Imam of our region' 2. The judge's (Qadi) jurisdiction is a town, whereas the jurisdiction of the Imam is 'the totality of the world' 3. Without the Imamate, all the rulings by judges (Qadis) 'in the regions of the earth' would be invalidated and all regional rulers/governors become invalid 4. The Fatimids argue that their leader is the 'true Imam' and therefore they call for everyone in the world to obey him (instead of Mustazhiri) 5. If the Fatimid claim that their ruler in Egypt holds the Imamate is true, the claim of Caliph Mustazhir to the Imamate is invalidated 6. The Abbasid ruler and the Fatimid ruler (despite being in two different regions) are contenders for the (singlar) Imamate position and if we prove the claim of one them is false, then the other's entitlement to the Imamate is proven 7. Even if the so-called Fatimid 'Caliph' was fit for the position of Imamate, he still cannot be the true Imam, because Imamate is by choice of the people and the Imamate of Caliph Mustazhir is affirmed by 'the leaders and ulema of the age and by all the masses of men in the farthest East and West' and 'obedience and submission to him is embraced by all'. Therefore the Fatimids are only a minority faction and outnumbered 10/1 amongst the Ummah and must choose the Imamate of Mustazhir as 'the true Imam' (over the Fatimid leader) 8. Caliph Mustazhir is 'the true Imam' because no one else is qualified for the position 9. Therefore the Fatimids are 'dissenters' and 'unjust' to claim the Imam/Caliph is anyone but Caliph Mustazhir Why were the Fatimids and Abbasids fighting each other, while denouncing each other's leaders as 'not the true Imam' if Ghazali understood that each region could have their own Imam or multiple Imams were permitted? Ghazali undoubtedly believed Caliph Mustazhir to be Imam of all the Muslims and leader of all Muslim lands and therefore they could be only one. It is why Ghazali writes 'the Imam charged with the truth whom all Men are bound to obey in this age of ours is the Imam al-Mustazhir billah' and 'all the ulema of the time must give the legal decision that men are definitely and positively bound to obey him...and that he is the Caliph of God over men and that obedience to him is a duty incumbent on all men.' Ghazali also wrote at the request of Yusuf bin Tashfin al Lamtuni (the founder of the Al-Murabitun) to the Muslims of Al-Andalus: 'Proclaiming the banner of the rule of Mustazhir (May Allah protect those put under His shade)', is the duty upon all leaders ruling over any region of the Muslim lands either in the East or the West, to make their pulpits decorated with supplications for the true Imam...They must listen and obey and firmly believe that obedience to the Abbasi Caliph is considered obedience to the imam ...And whoever rebels and disobeys the imam, the verdict applied to him is that of the baaghi ...and compliance to the command of Allah is to recognise the just sultan - the one who pledges loyalty of the true imam, to the Abbasid Caliphate'. Ghazali then concludes the fatwa, 'This is the judgment for any just Amir in any part of the earth' Ghazali also detailed how he actively lobbied for support for Yusuf bin Tashfin's cause, both at the Caliph's court and throughout the Muslim lands. The Seljuks proclaimed that they were working to unite the Ummah under the Abbasid Caliph and Ghazali was one of their key advisers, remaining in the court of the great Seljuk Sultan Malik Shah and his famous wazir, Nizam ul-Mulk, for at least six years. Ghazali proclaimed that the Abbasid Caliph's ability to wage war and defend Islam was supplied by the Seljuks: 'the requisites for the Imamate exists in Mustazhir billah...through the power of the Turks'. Moreover, Ghazali (and Imam Turtusi) famously supported Yusuf bin Tashfin of Al-Murabitun ('Almoravids'). Tashfin was a Berber leader who publicly declared his allegiance to the Abbasid Caliph and conquered parts of West Africa, Morocco and the Taifa states of Al-Andalus. Ghazali's 'movements' for re-unification were, quite simply, the Seljuks and the Al-Murabitun - who he and other scholars actively supported. In his 'Mustazhiri', as already mentioned, Ghazali proudly called the Abbasid Caliphate 'our conquering state' Full article appears here.