my nas keeps on waking up from sleep

i have a synology ds215j which is in my bedroom. inside it are two 4tb wd red nas drives. the main router is in the living room. i extended a long network wire to my bedroom and i connected another router to that network wire. i connected a short network wire from my router to a network switch and i connected another wire from the network switch to my ds215j. i am using the latest version of the dsm

the problem is that the ds215j keeps on waking from hibernation on its own and no one is accessing it. it hibernates for a random time between 5 minutes and 1 hour then it wakes up for few minutes and then it hibernates again for a random time and then it wakes up again and so on. the network light keeps on blinking nonstop when it's on. i am not using my nas for anything. i just mapped it to my computer as a network drive and that's it

either the router is causing the ds215j to wake up on its own or some setting in the operating system of the ds215j is causing it

if it's the router which is the reason then which setting do i change in it to stop my nas from waking up on its own? can i change the setting in the main router instead of in my router? i don't know the ip address for the settings of my router

also will this cycle of hibernating and waking up ruin the hard disks which are in the nas?

A short read of some pages found at synology ds215j at DuckDuckGo shows the DS or settings in it is most likely doing the job of enumerating the network.

Download Center. Synology Assistant is a desktop utility that searches for Synology DiskStations in the local area network. It helps you set up and install DSM on your DiskStation, connect to network or multi-functional printers shared by your DiskStation, setup Wake on LAN (WOL), or view monitored resources of your DiskStation.