On top of @Vr2Io's suggestions, it can be useful to limit the cores (cpu pinning) for downloaders such as deluge, particularly to exclude the cores primarily used by Unraid i.e. cores 0+12 in your case.
I've noticed deluge will use all resources available when moving files, I've seen it spin up 32 cores on my 1950X when I've moved multiple torrents.
Here is how my deluge instance is now configured
As mentioned, I also have a separate disk off the array dedicated to downloads.
Only the finished product (i.e. unzipped movie file) gets moved to array, while the torrrent and associated files stay on downloads HDD.
I set this up long ago on an unassigned device, but if your on 6.9+, setting up on a pool makes more sense.