Up to 1000 AD there Eastern Orthodox Church was still part of the Catholic Church, who indeed had apostolic succession. Due to doctrinal, theological, linguistic, political, and geographical disputes the the Partiach of Eastern Church and the delegate of the Pope excommunicate each other, and one thing let to another each claim to be the head of the Church. Mind you, this is an oversimplification of the said disputes. Better check your history books for a better picture.
Even now, both Catholic Church and Eastern Churches still has an unbroken line of apostolic successions, although each is also the claiming the title the head of the Church. In recent years there has been encouraging contacts for unification.
Coming back to your question, both Roman Catholic Church and Eastern Orthodox Church still has apostolic succession, and both are trying for reconciliation although it may not happened within our live time. But I am still praying for that.
Please also note that the term Roman Catholic Church only begun when Anglican started and the Anglicans wanted to claim they were also Catholic, then coined that they are Anglo-Catholic while the “others” are Roman Catholic.
God Bless.