Hi there
Having tried setting up plex a few times but never seem to have much luck whether it be 1080p or 4k streaming from a Synology NAS, had the same issue with the previous Synology NAS.
Details as follows:
NAS Model you have RS1219+ 16B RAM with 10gb ethernet back to the switch
DSM Version installed 6.2.3-25426 Update 2
PMS version 1.19.5.3112
In short, finding continual buffering like every few seconds then sits there for a few moments and might play another second.
Tried from desktop computer (10gbe) and Sony TV with the same result.
Any insight would be great, I can only imagine CPU based issue however not seeing spikes of any kind on the NAS.
Cheers