“Many square miles”?
Vatican State is only 109 acres (0.17 sq miles).
You’re quite an exaggerator!
They’ve had 1700 years of collecting knowledge and I doubt that they’ve thrown any of it away.
Just for the record.
What Do the Vatican Secret Archives Include?
The Vatican Secret Archives is home to the largest collection of Catholic books, documents, and doctrine in the world. It boasts letters from well-known figures such as Abraham Lincoln and Mary, Queen of Scots. It has been assessed to contain 53 miles (85 kilometers) of shelving, with 35,000 volumes in the selective catalog alone.
https://www.identiv.com/resources/blog/the-worlds-most-secure-buildings-the-vatican-secret-archives