Rumors of actual time travel have died down quite a bit. When the set pics dropped of a to-be-de-aged Indy, a lot of people assumed that meant time travel. But Mangold and Kathleen Kennedy have since confirmed that nope, the de-aged stuff is simply for the opening sequence, which takes place in the '40s.
That said, there's definitely a time travel element at play, it just sounds more like there's a MacGuffin that perhaps makes time travel possible, and maybe we even get a glimpse of its powers, but that the story itself isn't going full Endgame and actually jumping around in time as part of the plot. Who knows for sure, though...