You could also a try an approach to time outs where you invite the child to consider cooling down (if they are angry, frustrated, hyper, etc). They come out when they decide they are ready and together you can brainstorm solutions to the problem. (ie was somebody hurt and could use an apology, etc).
This teaches the child to notice when they are upset (a skill many older children have not learned!) and to take space to cool down (they can play music, read, whatever helps them), and then to actually come back to the problem and make a repair.
This is important because the purpose of discipline is to teach, not hurt, a child. Putting a child in timeout doesn't really send home any lessons other than when you are bigger you can boss smaller people around. And, talking during this process just makes you sound like the teacher in classic chlidren's cartoons (wah wah wah). This also means that if the child is not emotional beyond the point of functioning, then a time out isn't actually helpful - the purpose is for them to calm themselves. When they are not overly emotional then go straight to "Whoops, in this family we are helpful not hurtful, how can you repair this mistake?". Let them brainstorm and then pick something they can do.
I would rather help my child become better at self-reflection and self-regulation, understanding that mistakes are okay, and making repairs is necessary and genuine (ie not forced). Hopefully you can see how these skills will directly apply to the playground later (and eventually the workplace and beyond!).
Connected, genuine, respectful relationships with children is my best medicine for building children that are connected, genuine and respectful.