Agree. Laughable.
An oligarch is one of the select few people who rule or influence leaders in an oligarchy.
The word certainly was not around when John wrote, but certainly he could have written “ten rich men”.
Ancient Sparta was a military oligarchy.
What's the difference between Bezos or Musk or Buffett or Gates and with the kings around the time of Daniel?
Daniel wrote in 540 BC and had the Neo-Babylonian God-king-emperors and then the King-of-kings (Shahenshahs) of the Achaemenid empire. But the more common "kings" of that time were far less powerful than Bezos or Musk are today.