What was the Eastern Churches reaction to the Crusades. From my knowledge they were appalled by the actions of the Crusaders, and many saw it as Western Church trying to get a power grab, specifically the Pope trying to increase his own Power. Byzantine leadership was also pretty appalled, all they wanted was a secular reclamation of lost lands to muslims, not a full blown crusade.
enygma9753 pointed out some previous answers already, but I can give you another one of mine:
What was the Roman Empire's opinion of the crusades, and how did they feel about the outcomes?
Hopefully that helps...if not, we can try to answer any other questions you may have.
There's always more to be said, but in the meantime you may find some answers about the centuries-old tensions between the Eastern (or Orthodox) church and the West aka Roman (or Latin) church in this post by u/enygma9753 about the 1453 Siege of Constantinople by the Ottomans.
As outlined in the post, on-going differences over papal authority, untimely geopolitical events and lingering grievances over past wrongs by each side during the Crusades all played a role in the West and East's inability and reluctance to find common ground in the defence of Byzantium.