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PC: Successful Conciliarism paving to way to reconciling the Great Schism?

I'm working on an idea for a timeline where, amongst other things, the Conciliar Movement wins out. In addition to an earlier Reformation and more successful Ottoman Empire and Golden Horde this eventually leads to the Orthodox and Catholic Churches reconciling in order to provide a more united front against these new threats. I was wondering if this is likely?

Whilst there are still going to be theological disagreements between the Eastern and Western halves of the Church I figure that eliminating, or at least subordinating, the office of Pope and affirming the supremacy of Ecumenical Councils would remove one of the major political barriers to reunification regarding Papal Supremacy. In addition the "error" of Papal Supremacy and previous Popes could be used as a scapegoat for historical grievances and the prospect of future councils to discuss the theological objections to Catholic doctrine could help to smooth things over.
Conciliarism might lead to a reconciliation, but you've got it backwards- the stronger the Ottomans are the less chance of reconciling east and west. The Turks propped up the Patriarch to legitimize their rule in Greece, and emphasized differences to divide them from the latins. Meanwhile the Byzantine Emperor had submitted to Rome as the price of the crusade of Varna; a successful Latin led crusade which pushes the Ottomans out of Europe or even reconquers Asia Minor will legitimize reconciliation and improve support for the Byzantine catholic church.
A key factor in whether Conciliarism or Papalism prevails is how the emerging strong monarchs of the Late Medieval / Early Modern period position themselves. IOTL, they sided with the papacy (and ultimately settled all on the same pope again). To weaken papal authority in spiritual matters and strengthen that of Councils, you'd need at least some of the Catholic monarchs to side with Conciliarism.

Would it help mend the schism with Eastern Orthodoxy? There was a strong ecumenical push for it in the 15th century, too - and prominent conciliarists supported the idea. But with, say, the French or Castilian or English or Danish or Austrian monarchs being key in helping conciliarism prevail, things might go down an entirely different route. Nothing is set in stone, though. A Latin equivalent of autocephaly based on conciliarist arguments and monarchical backing would be interesting and basically butterfly the Magisterial Reformation (or pre-empt it).
Within the specific timeline I'm crafting the European Monarchs and other Feudal power structures have been significantly weakened and the Catholic/Orthodox world is on the backfoot. The Imperial Interregnum and Western Schism remain unresolved for longer, Sigismund dies much earlier in the Battle of Nicopolis and Wensesclaus doesn't exactly inspire much confidence, and the HRE remains fractured between several warring realms. Anti-Feudal and Communal revolutions have shifted power away from the rural nobility and towards the urban bourgeoisie. Powerful Lollard and Hussite movements have succeeded in establishing powerful realms across Christendom and remain a threat even in Catholic/Orthodox strongholds. The Ottomans take Constantinople 50 years earlier (amongst other things Timur dies much earlier) and the Emperor and Ecumenical Patriarch are in exile in Italy, whilst the Tartar Yoke under the dynamic leadership of Tokhtamysh is stronger than ever. Venice emerges as the political and economic hegemon over Italy, on account of all the other powers getting utterly wrecked in the upheavals and conflicts, including maintaining a corrupt hold over the Roman Papacy. In the East the Orthodox realms of Lithuania and Novgorod find themselves ruling over large Catholic populations following the collapse of Poland and the Teutonic Knights and are keen to see a reconciliation between the Churches as a means to provide unification and stability.

In this context of defeat and upheaval the remaining Catholic powers push for Conciliarism and autocephaly as a way to end the schism and create a united front, address many of the temporal grievances of corruption and wealth that people ad with the Church and ensure that the remaining Catholic secular leaders are able to retain, or even increase, their power whilst ensuring that none of them can establish a controlling influence over a unified Pope for their own benefit at the expense of the others. Further Ecumenical efforts at reconciliation look to address theological issues expand this to the Orthodox Church and maybe some of the more moderate Protestant movements.
As a follow up question, what would a Conciliarist Latin Church look like? I know that some of the more radical Conciliarists advocated things like all Christians should have a say in its leadership or outright abolition of the Papacy. I assume that an democratisation of the Church with congregations electing their own leaders like certain Protestant sects might be a bridge too far, even in the context of revolutionary political and religious upheavals, but I am interested in making something a bit more interesting than just retaining the same structures with Ecumenical Councils empowered to reign in Popes.