Whether standard server is suitable for the creation of UE4 MMORPG or better to write your own server?
I am working on writing backend MMO server software for UE4. Out of the box UE4 does not contain all of the components needed to create an MMO. Epic has explained that most of their licensees write their own MMO server software and just use UE4 as a client.
What I have done is create a hybrid system that still uses UE4 dedicated servers as instance servers and then chains them together to create a larger world. I wrote management server software to automatically bring instances up and down as needed across a server farm. The server software I wrote also has a SQL backend for persistent storage.