dCS only recommend one UPnP server software, MInimServer:
What hardware it is run on is down to you. Obviously QNAP or Synology are popular. There is a lot of information online about choice of disks which can be important if, for example, noise may be an issue if the server is in the same room as the audio system. Partly for this reason some of us ( like me) use a Melco streamer ( has inbuilt storage and is totally silent in operation) but only as NAS using its network connection. MinimServer provide custom versions for all of these options.
If you are seriously considering one then I would advise downloading the User Manual now to familiarise yourself with its operational attributes:
https://dcsaudio.com/documentation
dcS do not “voice” their products which are as neutral as possible. Yes, this could sound dry in combination with some amplification. Some prefer to use it in combination with a preamp rather than directly connected.