Should I buy this?

[TheDreadPirate]

Well, yea the firepro is not that useful probably but the Cpu should be beefy enough for that.

The question is... that thing probably burns through a solid 200 Watts+ while doing that.. I don't know where you from but with that power draw it probably makes more sense to go for an n100 based mini pc.

Honestly not sure it can. Encoding is not as parallel as most people think.  At some point, single threaded performance will more important and an 11 year old CPU probably isn't up to the task, IMO.  Even with 12 cores.

And the GPU is pretty much useless for transcoding.

I'm hoping this is something OP already had and not something they bought.  Echoing Efficient with the N100 recommendation for a basic, but capable, Jellyfin server.