So what could Daniel and Revelation be referring to when it talks about ten kingdoms in the last days?"
Ten kings - not ten kingdoms - in the text. Although likely to be ten leaders over ten nations - which those nations are part of the bigger overall union (kingdom).
The ten kings are ten kings of one overall kingdom. The fourth kingdom in Daniel 7:23-24, the Roman Empire. Which in the end times is the Roman Empire manifested as the EU.
In Revelation 17:17, the Antichrist person will have emerged as the beast-king, the ten kings hand their kingdom, singular, to him. My comment in brackets
Revelation 17:17 For God hath put in their hearts to fulfil his will, and to agree, and
give their kingdom [singular] unto the beast, until the words of God shall be fulfilled.
I.e. the ten kings agree that the beast-king will be dictator over their kingdom, singular, the EU.
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Here is what it boils down to. The person, who eventually becomes the Antichrist, goes through 5 stages. Being the Antichrist is one of the 5 stages.
1. starts as
the little horn person. The leader over a panel of ten EU leaders. The EU the manifestation of the Roman Empire in the end times.
2. then becomes
the prince that shall come of Daniel 9:26-27, into the middle east following the Gog/Magog event.
3. then becomes
the Antichrist, as the Jews will think that he is their long awaited King of Israel messiah. The person will be anointed the king of Israel by the false prophet.
4. then becomes
the revealed man of sin - when he unexpectedly commits the transgression of desolation act of 2Thessalonians2:3-4.
Ending his stage as the Antichrist, as the Jews will disown him as continuing as their king.
5. then becomes
the beast-king, after being assassinated for his claim of having achieved God-hood (Ezekiel 28:1-10). And then brought back to life by God, who will have great disdain for the person, in Isaiah 14:18-20.
As the beast-king, he will be the dictator of the EU, as the ten EU leaders hand their EU kingdom over to him, Revelation 17:17.
The beast-king's kingdom will be the EU. During his 42 months final reign over the EU, allies will likely be the U.S. and Canada. A powerful force militarily, combined - as the beast-king will be the king of the West in the Daniel 11:40-45 attacks on him near the end of the seven years. The attacks come most likely because he will be diverting all the middle east oil to his western coalition of nations.