For those who hesitate to try Roon on an older Synology NAS. I installed Roon server on a 6 year old Synology NAS 216 II+ - Celeron and 1 GB > it works, at least sometimes.
After checking the NAS system I upgraded to 8 GB for little money. Now it works fine, 2 end points max. I am happy with roon now!
Mery X-mas !