New CPU Seems to be unable to handle FFMPEG?

[TheDreadPirate]

For a while I ran Jellyfin on an Intel J4205 with 4GB of RAM. It was a super low power and slow CPU, but the Intel Quick Sync in the iGPU was new enough that it worked really well for Jellyfin.

RAM is not the problem in your case and getting more RAM is not the solution. The old CPU is just not nearly as fast as your laptop and the version of Quick Sync in the iGPU is not well supported in modern Linux. And the codec support wasn't great anyway. And it is probably CPU transcoding, which is kind of slow even on a fast CPU and super slow on older CPUs.

We recommend 7th gen Intel CPUs and newer. Their Quick Sync is sufficiently capable for modern media and Intel still supports them in their drivers.

Your options are 1) pre-transcode your media to avoid transcoding or 2) get newer hardware. If you are in the US, surplus office PCs with 7th and 8th gen Intel CPUs are plentiful and cheap.