My book The Rise and Fall of the Papacy deals with the Synod of Douzy and the deposition of Arnulf of Reims. In both cases it cites these councils as consistent with consensus-based ecclesiology based upon the evaluation of secondary sources. Thanks to Evangelos Nikitopoulos of Scriptorium Press, excerpts of these documents have been translated as follows.
Synod of Douzy (871 AD)
To the most holy and reverend father Hadrian, Pope of the first see of the Holy, Catholic, and Apostolic Roman Church…We fervently beseech your authority to free us from the government [of Bishop Hincmar of Laon]—which we have for long been unable to bear— as from a great and incorrigible pest…And if, for the time being, it does not please you to put your seal [roborando] on what we have already lawfully decided (in this Synod)…may he at least not be restored to his see until he first be re-tried in this province, as the rules and laws require. For until today, no decree of the Fathers has ever denied this (privilege) to the Churches of France and Belgium; considering especially that the decrees of Nicaea have most aptly committed the lesser clergy and even bishops (as the African Council writes) to the authority of their Metropolitans. And as Saint Boniface himself explains, writing to Bishop Hilary of Narbonne, ‘It is proper for us to be diligent guardians of the paternal rules. For no one is ignorant of the constitution of the Nicene Council which decreed that individual metropolitans ought to have jurisdiction over a single province, and that no two provinces should be under the rule of one…’
And if—far be it—by some suggestion or request, [Hincmar] wrest a decision from the Apostolic See to be restored to his rank as one scorning and treading upon the holy canons…we will hereafter not recognize any of his decisions, just as until now we have not communed with his deeds by resisting them. For our own Holy Fathers, who still live with us through their canons, being distinguished in the way of the Holy Scriptures and the tradition of the Apostles and inspired by the grace of the Holy Spirit, give certain judgment about these things…May he live as he sees fit, for the Apostle both reassures and advise us: ‘Have no fellowship with the unfruitful works of darkness, but rather reprove them.’ (Epistola synodalis Concilii Duziacensis ad Hadrianum II Papam, in: Concilia Antiqua Galliae Supplementa, ed. Pierre Delalande, Paris: 1666, pp. 259-261. The quote from Pope Boniface is from Epistle 12, Patrologia Latina 20, col. 773)
The Letter of Gerbert of Aurillac (later Pope Sylvester II) in favor of the deposition of Arnulf of Reims vis a vis the Pope locally rejecting the Frankish’s synodical deposition (993 AD):
Shall they prove that the Roman bishop’s judgment is greater than God’s [i.e. that of the local synod of bishops, cf Canon 134 of Carthage 424]? But the first bishop of the Romans, indeed, the prince of the Apostles themselves, exclaims: ‘We must obey God rather than men.’ Paul, that master of the world, also exclaims: ‘If any shall preach unto you anything other than that ye have received, even an angel from heaven, let him be anathema.’
Because Pope Marcellinus burned incense to Jove, did all bishops, therefore, have to burn incense? I firmly maintain that if the Roman bishop himself shall have sinned against his brother and, though often advised, shall not have listened to the Church, that Roman bishop, I say, is to be considered a heathen and a publican according to the commandment of God. For the loftier the position, the greater the ruin. Even if he considers us unworthy of his communion because none of us will join him against the Gospel, he will not be able to separate us from the communion of Christ…
Let us not give occasion to the envious to think that the episcopate, which is one as the Catholic Church is one, should seem to be subject to one man; so that, if he be corrupted by money, favours, fear, or ignorance, there could be no bishop but he whom such virtues would commend. Let the common law of the Church be the Gospel, the Apostles, the Prophets, the Canons established by the spirit of God and consecrated by the reverence of the entire world, and the decrees of the Apostolic See that do not disagree with these; and may he who would depart from them contemptuously be condemned by them and be rejected. But may he who keeps and observes them as he is able have continual and eternal peace. (Patrologia Latina 139, col. 267-268)
As the preceding shows, even with the wide circulation of the Pseudo-Isidorian Decretals, the West did not have sudden amnesia of the original ecclesiology of the Church. This is something that creeped in due to the canonical reforms of the 12th century and on, as well as the Crusades placing the Papacy as a mediator in solving jurisdictional claims.
Orthodox Christian Theology 
We can also see this eclesiology in the Letter of the Church of Liege against the Pope Paschal II, 1103 AD.
“We hold to our Bishop, Archbishop, Provincial and Regional Synods from Ancient Tradition; and whatever has been defined there from the holy writings, *is not referred to Rome* unless it regards more serious affairs concerning which an authority is not found in the holy writings. But *we reject in every way those legates heading out from the side of the Bishop of Rome and rushing here and there filling their pockets, just as the African Councils in the times of Zosimus, Celestine, and Boniface have shown.* For – that we may recognize them from their fruits – not the correction of morals, nor the emendation of life, but rather the killing of men and the depredation of churches are the result of their actions. Therefore, because we cling to the Ancient Rule and are not carried away by every doctrinal breeze, behold, this is why we are called ‘excommunicates’.”
There was no such “Pope” as “Paschal II”. There was such an apostate AntiPope as “Paschal II”. The apostate AntiPope “Paschal II” invalidly “ConSecrated” the already-DeSecrated Cathedralis Sancti Evasii with jew-Masonic-Satanic symbols and the Egyptian-Greco-Roman pagan mythological, otherwise idolatrous, pornographic, otherwise immodest, secular, and otherwise grotesque images against Faith and Morals in Casale in Monferrato in 1107 [medioevo.org/artemedievale/pages/piemonte/Casale.html] just as the apostate AntiPope “Innocent II” invalidly “ConSecrated” the already-DeSecrated ArchAbbey with images against Faith and Morals in Cluny in 1130 of which even the apostate Bernard D’ClairVaux spoke of but also never sufficiently condemned by sins of omission and other reasons currently outside the scope of our messages. Your meetinghouses have such desecrations too. Here’s just 3 examples.
A few apostate AntiMonasteries on Mount Athos in Greece have the pseudoilluminati eye of “horus” on their front exteriors and in the interiors on the sides of Satan’s altars.
The AntiMetroPolitan-AntiCathedral-AntiBasilica of the “AsSumption” of “our” AntiLady of Valencia in Valencia in Hispana has the jew-Masonic-Satanic hexagram on its exterior.
The apostate AntiCathedral of Armed Forces was completed in 2018 and desecrated with images against Faith and Morals in Patriot Park in Kubinka in OdintsovSky DiStrict in Moscow-Oblast a.k.a. Podmoskovye in Russia in 2020. Here are the (listed) desecrations. Here’s an immodestly dressed warrior with a long spear on a horse (on the outside). Here’s a bunch of apostate (Photian-Kirillic) neoPlatonic Greco-Russian (CæsaroPapist) unorthodox AntiSaints (on the outside of the main entrance which looks like the Orc Fortresses from the Lord of the Rings and something from the WarHammer or Doom series). Here’s superstitious iconography of apostate (Photian-Kirillic) neoPlatonic Greco-Russian (CæsaroPapist) unorthodox Union of Soviet Socialist “RePublics” modern war propaganda nostalgia (e.g. a blasphemous apostate (Photian-Kirillic) neoPlatonic Greco-Russian unorthodox CæsaroPapization of the Icon of the Saviour Not Made by Hands which is a Canonical Image of the Sacred Face of Christ Jesus of Nazareth surrounded by sacrilegious Muscuvitizations of the TheoTokos accompanied by apostate Photain-CerulArian Greco-Russian CæsaroPapist AntiSaintly warmonger soldiers, generals, guns, tanks, aircrafts, and more) and the floors paved with ashkenazi sozi metal trophies (e.g. weapons, tanks, and more) to remind the apostate (Photian-Kirillic) neoPlatonic Greco-Russian (CæsaroPapist) unorthodox of the idea of the “Great EmPire” which you have to “pray” for which smells too fascist. Here’s an AntiMosaic of the contemporary Russian State (e.g. Vladimir Putin himself and his minions). Here’s an AntiMosaic of the contemporary Russian State and (Photian-Kirillic) neoPlatonic Greco-Russian (CæsaroPapist) unorthodox AntiChurch (e.g. Russian soldiers in front of a Muscovitist cult). Here’s a Marxist-Leninist-Stalinist symbol infront of a star which symbolizes Baphomet’s head upsidedown (in the tint glass).
The great apostasy started when Satan was unchained in 1033 but tell me more about how y’all (neoPlatonic Greco-Russian unorthodox, Frankish Latin uncatholics, Lutherans, anglicans) ain’t pagans on this point alone just for worshipping inside meetinghouses with jew-Masonic-Satanic symbols and the Egyptian-Greco-Roman pagan mythological, otherwise idolatrous, pornographic, otherwise immodest, secular, and otherwise grotesque images against Faith and Morals inside and outside them.
Hey Miguel, you forgot to mention the evil lizard men that secretly control the illuminati and the PhotIANCerulianGRecoRUSianhunishslav HeReTiCs.
Hey Stefano I forgot nothing and your leaders are still Satanists.