I will not speak for
all Orthodox, but many Orthodox I’ve spoken to on the Internet (there’s very few here in Spain) bluntly and specifically state that the Catholic Church lost Apostolic Succession in 1054 and ever since then, no Catholic priest has ever celebrated a single valid sacrament. One even told me that baptism isn’t even valid.
Obviously, I do not accept this argument, not because I’m going to become Catholic of course, but because schism itself isn’t an absolute deal-breaker as far as validity of Sacraments go. Churches like the Oriental Orthodox (Copts, Armenians, etc.) or the Assyrian Church of the East split off from the Church
much before the Schism of 1054, and to this day, they still have valid sacraments.
And I’ve heard talks of Eastern Orthodox and Oriental Orthodox wanting to be in communion with each other, and they’ve been separated from each other longer than Eastern Orthodox have been from the Catholic Church. Yet many Orthodox bluntly deny our sacraments yet want to establish communion with churches who were historically linked to non-Chalcedonian Christology (which is of course not really the case anymore, as Popes and Patriarchs from those churches have met and have come to the conclusion that it’s not really non-Chalcedonianism that they espouse, but that is not the point). Go figure.