The American federal government has more or less the same number of employees as it did in the 1970s.
But this neglects the millions of contractors and other positions that are also funded by government spending, which is harder to measure, and does change more over time.
https://www.brookings.edu/articles/the-true-size-of-governme... (2020, but the article doesn't clarify if the 5m includes short-term census workers)