PRO/MMO Foundation. Free, open source, multiplayer tools built to scale

Is there a way to not use your servers and use our own?
We were exploring using Unreal for our next MMO after seeing Fortnight but this thread has really made us step back due to the constant mentioning of the ‘limitations’ that the engine has.

The ‘engine’ our current games is using was developed over 15 years ago and took quite a while to complete. We were looking at Unreal in order to speed up development of our game and implement it with the latest graphics much faster than we had done before. When you get my age, you just want to work smarter. These tools seem like a big plus that they would make things much faster to develop, but now we are questioning if the engine is even capable of doing what we require.

A single dedicated server hosted in a Tier III data center is a linux machine with dual E5-2650 (24 cores total) and 64GB memory.
We run 20 persistent world maps and 46 squad based ‘instances’.
We are in the process of adding 12 more world maps and 7 more instances.
10TB bandwith
We have just over 4500 accounts/players
At any one time we never have over 500 players but could easily handle 1000.
We have separate servers for website and patch server

Am I right in assuming at this point that Unreal is unable to handle multiple world maps and 500-1000 players on a single server?