All the beards, ancient clerical vestments, stunning churches, and liturgy aside, the Russian Orthodox Church has always been just another national, heretical and schismatic church, and since the time of Stalin is controlled by the KGB.
The Vatican today tries to maintain political relations (dialogue) with every country in the world, no matter how evil (Cuba, China, Vietnam etc.) The Russian Orthodox are just one more to dialogue with. "Dialogueing" with them does not legitimize their heresy and schism one bit.
The dogma can never be changed by this pope, the heretical and schismatic, "unless they are joined to the Church before the end of their lives, cannot share in eternal life, and will go into the everlasting fire which was prepared for the devil and his angels", even if they shed their blood for Christ:
Pope Eugene IV, Council of Florence, “Cantate Domino,” 1441, ex cathedra:
“The Holy Roman Church firmly believes, professes and preaches that all those who are outside the Catholic Church, not only pagans but also Jews or heretics and schismatics, cannot share in eternal life and will go into the everlasting fire which was prepared for the devil and his angels, unless they are joined to the Church before the end of their lives; that the unity of this ecclesiastical body is of such importance that only those who abide in it do the Church’s sacraments contribute to salvation and do fasts, almsgiving and other works of piety and practices of the Christian militia productive of eternal rewards; and that nobody can be saved, no matter how much he has given away in alms and even if he has shed blood in the name of Christ,, unless he has persevered in the bosom and unity of the Catholic Church.”
Now, yes, the Catholic Church has always recognized the validity of all the heretical and schismatic clergy with proper apostolic succession, the so-called Eastern Orthodox being a later heresy, also has valid clergy and sacraments, however, ALL of their sacraments are of no efficacy to someone who is outside the Catholic Church because of heresy and schism. The sacraments are real, but the recipient is in a state of sin, in his heresy and schism, (and other sins, like adulterous 3rd marriage, permitted by the Orthodox), therefore, in a manner of speaking, one could say that the very next second, the state of sin returns. This is why Cantate Domino says "only those who abide in it do the Church’s sacraments contribute to salvation and do fasts, almsgiving and other works of piety and practices of the Christian militia productive of eternal rewards".
Anyone who receives the Sacrament of Baptism, whether in the Catholic Church or in a heretical or schismatic church, receives the whole Sacrament; however, he will not have salvation if he has that Sacrament outside the Catholic Church. Eternal life can never in any way be obtained by anyone who, with the Sacrament of Baptism, remains a stranger to the Catholic Church. Hold most firmly and never doubt in the least that no person baptized outside the Catholic Church can become a partaker of eternal life if, before the end of this earthly life, he has not returned, and been incorporated into the Catholic Church. (St. Fulgentius)
Some men can receive Baptism outside the Church, but no one can either receive or possess salvation outside the Church. For the water of the Church is salutary and holy for those who use it well, but outside the Church no one can use it well. (St. Augustine)
There are many heresies which utilize the words of Baptism, but not in a proper sense, nor with sound faith; and, in consequence, the water which they pour is unprofitable, so that he who is sprinkled by them is polluted rather than redeemed. (St. Athanasius)
Although among heretics and schismatics there is the same Baptism, nevertheless, remission of sins is not operative among them because of the rottenness of discord and wickedness of dissension. (St. Augustine)
Baptism does not profit a man outside unity with the Church, for many heretics also possess this Sacrament, but not the fruits of salvation. Children baptized in other communions cease to be members of the Church when, after reaching the age of reason,they make formal profession of heresy, as, for example, by receiving communion in a non Catholic church. (St. Augustine)
You may want to do some study:
And also you may want to read the Catechism of the Catholic Church