I’m not sure you need a GPU, and Jellyfin docs state:

AMD is NOT recommended if you plan to use integrated graphics for Jellyfin.

I don’t run Jellyfin but my NAS is also TrueNAS and it’s just a J5005-ITX Mainboard with integrated cpu that costs around 100€ used. I’ve seen similar newer ones with n100 with 6 SATA ports. Pretty sure you don’t need an 8 core and you mentioned power consumption is relevant.