One Church has a decentralized authority that recognizes that it is impossible for mankind to be infallible (there have been many patriarchs that were in error throughout history for instance, including the current Ecumenical Patriarch of Constantinople Bartholomew), while the other straight up has a doctrine telling you not to convert jews.
Convert or not, it's being influenced by jews anyway. It's not a matter of doctrine. Both are not what they are supposed to be.
Look up why Soviets brought back Orthodox church.
Varying nations use their Churches as a vassal to push ideals that promote the longevity and glory of said nation. However, just because the Moscow Patriarchate fell victim to this vassalization and some of the Greek clergy pitted themselves against Germany does not mean all of Orthodoxy is compromised. ROCOR, which mainly has parishes in America, was largely resistant to bolshevik jewish movements.
I looked up ROCOR, and I'm surprised to see that kikes are kvetching about them and calling them antisemitic.
Then you have Serbian Orthodox church which is pushing holocaust lie 24/7. They mostly grovel to the kikes, but here and there produce something based.