Caching "Up Next" episodes

[TheDreadPirate]

Jellyfin has no awareness of what kind of storage your media is on so this kind of SSD caching is almost certainly not going to happen due to the sheer amount of work needed and because it is an edge case.

What you're describing sounds like it is extracting subtitles or attachments and it is taking a long time. This is usually due to either slow storage or an underpowered processor. On-the-fly extraction SHOULD take 1-2 seconds most systems.

Share your logs via pastebin so we can confirm what is going on.

You could try installing the "subtitle extract" plugin so that it pre-extracts subtitles and attachments.