You can, but for media serving and transcoding you ideally want Intel Quick Sync, and it's simpler to have separate systems for your Quick Sync system and your "many cores" system.
(You might want to upgrade your transcoding box to a newer generation processor that supports, say, AV1 encoding.)
And FWIW my Ryzen Embedded system isn't especially low-power by design, it was just the most accessible way of getting ECC memory for me.
Can do the same with various GPUs, but Quick Sync tends to be the lowest-power and most well-supported at the software level.