Republic back then meant commonwealth with any form of government. The Dutch Republic was loose union of seven provinces. Republic changed to mean democratic government by representatives without monarch.

It need not be democratic in the modern, universal suffrage sense.

Netherlands was not. It was a republic of oligarch-run states. They did not have even landholder suffrage until halfway through the 1800s.

Like the People’s Republic of China, the Democratic People’s Republic of Korea, and the Union of Soviet Socialist Republics? Those ones?