I wouldnt worry at all, your hardware seems to cover your needs more than sufficient! Especially those disks! (In Raid 0 or 1?) 
The CPU consumption seems a bit high compared to my own experience but on the other hand the RAM seems underused.
Have a look at my data here if you like:
I dont see any reason for other services or functions to step in and affect your Roon system in any way, other than self inflicted. (If you decide to use the QNAP as a movie player at the same time connected to your TV or similar)
Atb Mike