p2p connection, means listen server not dedicated.
Theoretically it is possible to code system where one of players gets into zone, starts hosting it, and rest can join. However i never heard about such plugin for unreal.
But then you will have multiple servers in network. So either you need to code some supervisor for network connections, or dig really deep into unreal network code. And then whole supervisor will be just fancy name for a lobby.
I am also unsure how unreal open world maps behave with listen server in multiplayer.