In the article "The King of the North" in the Time of the End in the May 2020 Watchtower, pp.2-7, paragraph 5 says :
At some time during the second century C.E., the true Christian congregation began to be overrun by false Christians ... From that time until the late 19th century, there was no organized group of God’s servants on earth... Why is that fact significant? It indicates that what we read about the king of the north and the king of the south could not apply to rulers or kingdoms that held power from sometime in the 2nd century to the second half of the 19th century. There was no organized group of God’s people for them to attack.*
The footnote (*) reads :
For the reason stated here, it no longer seems appropriate to list Roman Emperor Aurelian (270-275 C.E.) as a “king of the north” or Queen Zenobia (267-272 C.E.) as a “king of the south.” This updates what was published in chapters 13 and 14 of the [1999] book Pay Attention to Daniel's Prophecy! [pp.240-241]
The identification of Zenobia with the King of the South in the third century C.E. had been consistent since 1891 (in the volume Thy Kingdom Come, pp.32,33). You can read more about her in Pay Attention to Daniel's Prophecy!, pp.252-255.