UE4 Custom Dedicated Server (collision, hitboxes)

So I am currently developing a custom dedicated server in UE4
from scratch. I use RakNet as a networking engine and want to achieve
the typical dedicated server that can manage adding players to the world, hitboxes, collision
and verifying packets in general. What I mean by verifying here is e.g. if the server receives a movement packet
it can decide whether the packet’s sender can move there or not.
I see the biggest trouble in verifying the e.g. movement packets and hitboxes because
the server has to have access to the world and collision methods of unreal which I don’t know how to do
from scratch.
Is it possible to get the base server from UE4 and equip it with your own
networking engine and packet handling? Or is there a better way to achieve my goal?