Read Roon’s system requirements article to find that you’re below recommended spec with your choice.
It might just work and may even be better than your NAS, but happy you likely won’t be for long…
In all probably, if you successfully install ROCK, this device will work, but perform poorly, which means that the UI will be sluggish on all devices, and scanning, DSP, or searches could interrupt playback.
Moreover, if you run into issues and need support, the response will be clear: you’re not running on supported hardware.
This should be absolutely fine since the OP has around 5k albums. I run my i3 NUC on 8 GB, but the only reason for this was availability of 4 GB pairs. Processor–or rather single thread performance–is key here, and this Celeron just doesn’t cut it (~50% performance of my i3.)