What is the end times of the RCC? Am I correct that it is amillenial?
Correct, although you will not find many Catholics who identify themselves as amillennialists. We do not overly concern ourselves with the timing of particular eschatological events since that is for God alone to know.
For a good overview of Catholic eschatology, look here: catholic.com/library/rapture.asp
Correct, although you will not find many Catholics who identify themselves as amillennialists
Is it an essential of the RCC faith?
Amillennialism? No, in that there isn’t any Church teaching that I know of that gives a definition of amillennialism and then requires all the faithful to believe it. That being said, there are various Church doctrines that fit the amillennial view and actually conflict with parts of the various premillennial and postmillennial eschatologies.
To get an overview on what those are, read this relatively brief portion of the Catholic Catechism: scborromeo.org/ccc/p1s2c2a7.htm. If you have some questions about it I’d be happy to discuss them.