There was a sci-fi book written about 50 years ago that postulates that time is quantum-like and sort of like the stills from a movie. Between each quantum of 'your' universe's time, there's space for billions of quantums of 'other universe's' times.
"Occam's Razor" -https://www.amazon.com/Occams-Razor-David-Duncan/dp/B000O8GD...