This is wrong and has been debunked many times.

See for example https://www.thoughtco.com/republic-vs-democracy-4169936 or https://www.theatlantic.com/ideas/archive/2020/11/yes-constitution-democracy/616949/ (archive: https://archive.is/FbuL5 )

Granted, some specific decisions like the EC could have gone better. But overall, the US is a democracy - specifically a representative democracy.

In fact, to say otherwise is a major GOP talking point. For example (from the Atlantic article),

Republicans such as Senator Mike Lee of Utah have taken to reminding the public that “we’re not a democracy.”
It is quaint that so many Republicans, embracing a president who routinely tramples constitutional norms, have suddenly found their voice in pointing out that, formally, the country is a republic.

Of course the counter example is a theocratic republic. A living example? The Islamic Republic of Iran.

Iran citizens living in Iran vote for their President, https://en.wikipedia.org/wiki/2024_Iranian_presidential_election#Opinion_polling_and_forecasts

They also vote for their version of “member of Congress” (ok so they don’t call it Congress), https://en.wikipedia.org/wiki/Electoral_districts_of_Iran & https://en.wikipedia.org/wiki/Islamic_Consultative_Assembly#Constituencies

But while the President of Iran is the head of government there, he’s second to the divinely appointed supreme leader, https://en.wikipedia.org/wiki/Supreme_Leader_of_Iran (in practice the SL appoints members to a Guardians Council, who vet approve members of the Assembly of Experts, who reappoint the SL - a bunch of silly layers for the SL to basically elect himself) - so this is a republic where folks technically have their representatives but the power lies elsewhere.