So the idea is there is a closed loop. There are events that initiate the plot. And by the end we realize the characters we’ve been following are responsible for those events. Thus creating a never ending cycle.

But at the end of the series, 1 of the characters just decides to do something different. This ends the loop. But why did that character change his behavior? Only reason I could find is to make an ending for the show.

It’s a time loop story where the loop ends by characters behaving different than they did in any other iteration of the loop and for no particular reason.