Yes, Congress does have that authority. The Supreme Court has ruled that Congress can subpoena private citizens, but in limited cases and circumstances.
We live under Supreme Court rulings on what the Constitution says and right or wrong they have been given the power to determine that.
This issue came up very early in America’s past. Most of the Framers were still alive when the debate over “judicial review” was raised. Many of them accepted judicial review and that is why the Supreme Court now determines what the Constitution says.
It’s as I said, Congress doesn’t have the “constitutional” authority. Any opposite SCOTOS is incorrect.