How to make event begin overlap detected and triggered by the server? Or if it has to be detected and triggered on the client, how can the server verify that there should be a collision? Because this event is often used to trigger the apply damage call, if the client can cheat on the event begin overlap, how can the server know that the event begin overlap on the client is true? Or is it possible to run physical and collision detection on the server?
You can do everything on the server but you still need to do it on the clients too or they will complain about lag depending on the feature.
Sometimes you can get away with everything happening on the server and sometimes you also need to do it on the client and conciliate the client if the client prediction was wrong. Client reconciliation can be difficult to get right and it should be avoided as much as possible by improving the prediction or simply wait for the server to give the result.
So how to make the event to trigger on server?
Every Actor spawned by the server except input events gets triggered.