I think Revelation is the first book of the NT written but not that last half. Only 6-11. It deals with events in the 59-73CE time of Jerusalem's destruction. Note Jesus is hardly mentioned in those chapters..
Later in the 90s it might have had the beginning added and 12-16 added. The writer John of Patmos for all we know could have been the rebelious Jewish leader John in the Jewish war but this can't be concluded for sure. Whoever it was it was horrble greek. 17-22 are almost in the late second century from the kings list.
The Gospel of John is dependant on the Gospel of Pontius Pilate and the Gospel of Nicodemus which places John in the 100-120CE area. The other gospels came after the first being the pre-Lukan version by Marcion in 140