Taking fiction aside, if there were a real-life non-lethal vigilante, how would the criminals they catch legally go to prison? The vigilante broke the law to gain evidence, so all the evidence the vigilante obtained would be thrown out, and every criminal would walk. As messed up as it is, The Punisher and Dexter make sense, because the only way a vigilante can really be successful is if he just straight up kills the criminals.
In the US there’s a concept called citizens arrest where in some states you’re able to detain people after they committed a crime. That’s it though. It’s also not recommended that anyone ever do it, because it can very easily cross the line into false imprisonment, kidnapping, or some other crime.
Citizens arrest is a common concept: https://en.wikipedia.org/wiki/Citizen's_arrest