I would not buy a CPU without seeing a real-world measurement of idle total system power consumption if you're concerned about energy (and therefore cost) efficiency in any way. Especially on desktop platforms where manufacturers historically do not care one bit about efficiency. You could easily spend many hundred € every year if it's bad. I was not able to find any measurements for that specific CPU.
Be faster at transcoding video. This is primarily so I can use PhotoPrism for video clips. Real-time transcoding 4K 80mbps video down to something streamabke would be nice. Despite getting QuickSync to work on the Celeron, I can’t pull more than 20fps unless I drop the output to like 640x480.
That shouldn't be the case. I'd look into getting this fixed properly before spending a ton of money for new hardware that you may not actually need. It smells like to me that encode or decode part aren't actually being done in hardware here.
What codec and pixel format are the source files?
How quickly can you decode them? Try running ffmpeg manually with VAAPI decode, -c copy, and a null sink on the files in question.
What codec are you trying to transcode to? Apollo lake can't encode HEVC 10 bit. Try encoding a testsrc (testsrc=duration=10:size=3840x2160:rate=30) to AVC 10 bit or HEVC 8 bit.