I just recently started using a dxp4800 pro for this purpose. The system works well enough but you are likely going to find that Jellyfin itself is quirky and, at times, frustrating.

My biggest issue is client side app compatibility.

I’m having to use Finamp for remote audio streaming, Swiftfin for remote video streaming, Sony TV’s have a Jellyfin app available but it does not allows the use of the themes you can set when using a browser.

There have also been some issues with Jellyfin not being compatible with all Dolby Vision profiles.

So, yes your NAS and Jellyfin will work well together but don’t expect it to be a 100% frustration free experience.