“The authors of the Old Testament had limited geographical knowledge “
God was the Author of both the OT and NT, and He had a clue about geography. Most End Times references are in the NT.
I expect that the humans who penned the Scriptures were wondering about the cryptic nature of the text because, as you say, they had limited knowledge.
Anyhow, most theological scholars believe that while Russia is referenced re End Times, America isn’t, so that’s a bit scary.
Reminds me of the famous “Secrets of Fatima.”