I remember this scene from Doctor Strange where the good doctor used the Time Stone to trap the demon Dormamu in a time loop. Every time Strange was killed, the time loop would restart until Dormamu agreed to Strange’s demands. This was an ideal way to trap and coerce an overpowered supervillain, but I have pondered on an alternate version of using a time loop.
If you had the power of using a time loop, then you would have a wonderful way of coercing people into doing whatever you want. During the time loop, you would have the freedom to torture and kill these individuals however you want. When they die, the time loop restarts, but they are left with the memory and pain of dying repeatedly. When they eventually break and agree to your demands, then you release them from the time loop.
I am thinking of doing something like this in my new superhero series where my main character does just that. With his power level, he would have an infinite variety of ways to torture his time loop victims. You will also get to see a sadistic side of the character. He will be doing the right thing but with the wrong methods. That will add moral ambiguity to the character.