The End of Eternity (1976)

Somewhere outside of time as we understand it is the timeless realm known as Eternity, where a group of highly trained technicians – drawn from all the Centuries under their control – have manipulated the Earth’s history to transform it into what they believe to be a perfect world, free from every disaster and hardship. But when Senior Computer Twissel sends a young Technician named Harlan to study the 480th Century in the company of a seductive woman, Harlan begins to suspect that Twissel may have some secret plan of his own which has something to do with the forbidden centuries before time travel was invented...

Unfortunately the movie The End of Eternity is not yet available on HBO Max.