Hello,
The dedicated server would give huge boost for players playing online. As for porting to Linux, it is not so tedious task if the game is written on C/C++ or other well known programming language. They all have cross-platform compilers which allow to run code on any popular OS. The main difference between Windows and Linux programming is the graphics card API which is mainly DirectX for Windows and OpenGL for Linux. But as far for the dedicated server it does not require any graphics. So should be at least be worth to try make copy of the server code from the game and try compiling it for the external binary:) As for the hosting on Linux servers it is one of win-win situations with for the multi-threading/multi-CPU performance (the OS kernel is designed for multi-user and multi-process) and hosting prices.
As an example you can take a look how Ark Survival Evolved game gone through development and post-production and how they did grow up player base. The dedicated MP servers was the key for the community. 2 years later it is still popular game and people keep playing on the dedicated servers.
Cheers!