Since the actors are replicated from the server to client (not the other way around!), you’ll need to execute all actions that should affect all players on the server.
Basically, in addition to the Teleport function, create a custom event (in the same Blueprint) that calls the matching function. In the Details panel of the event, set the Replicates property to Run On Server. Then replace your current function call with a call to the event instead.
The server will take care of moving the character and then, because the characters and their movement are replicated, inform all clients about the updated location.
The same applies to spawning and destroying actors.
I found this video series extremely helpful:
Also, right now your characters will always teleport into a fixed direction. If you want to make this depend on their current rotation, you can use the GetForwardVector:
Good luck!
PS: Try cropping your screenshots. They’ve got these huge white borders right now.