Its mainly about the authority of the Pope. Otherwise, both the Catholic Church and Orthodox Church have the exact same sacraments, and Catholics recognize the Orthodox as having legitimate apostolic succession and their sacraments as valid.
One should focus on the 99% that unites us, vs. the 1% that doesn't
“Its mainly about the authority of the Pope.”
Yes you are correct about all that. My best friend is Greek Orthodox and I was surprised to find their sacraments and practices totally mirror Catholicism. These day even many Catholics are starting to question the legitimacy of the current Pope.