I’ve been using an OWC “raid drive” (Thunderbay 4) for this very purpose for about a year and a half now, with 100% positive results. I have about 10 TB of audio-video files that I keep online on my home network. I do not have the Thunderbay configured for RAID, however; I have it stuffed with four 8 TB drives that are configured to run independently. My AV files are distributed across them using TuneSpan (a major driver in keeping me at Mojave since TuneSpan uses iTune’s XML file list to track files–the new, “improved” individual programs do not use XML, and TuneSpan is not likely to be updated).
So I’ve got TV shows (iTunes downloads, DVD rips, OTA recordings) on one drive, movies on another, and high resolution audio files on a third drive. Speed is great–the mechanical hard drives are never the limiting factor in performing any operation. And now, 14TB drives are the new 8TB drives–price per TB on spinning drives keeps going down as their capacities keep going up.
I have not used the Thunderbay configured as an actual RAID because of TuneSpan’s ability to automatically move new files to specified locations. I have the earlier, Thunderbolt 2 model which works great with my “server,” a 2013 Mac Mini.