While it’s possible that some aspects of the Han Solo movie will deal with earlier points in time, we expect the vast majority to take place in a period more or less immediately preceding the first Star Wars movie.
Most importantly, the bulk of this story takes place when Han Solo is under 20 years old.
We’re not necessarily postulating that Woody Harrelson will be playing this exact character in this exact story.
Still, they could very easily shift some of the events of a story like this until later in both of the characters’ lives.