A way to configure (increase) continuous buffering size / cache for streaming video

[tdbe]

Been looking at jellyfin and on an average wifi, for a 4k video shot on my phone, it buffers for like 20s for every 10s of content. There should be a clear setting where anybody can tell it "buffer x minutes (or megabytes) of content before starting to play".

We could go down the rabbit holes of "why isn't my wifi perfect" or "is it transcoding and at what quality" but let's put it simply as an average user:

• youtube.com just works at 4k without stutters / interruptions.
• SMB and internet work at 20-50 MBytes/s [EDIT: and actually via wifi it can be patchy, but this doesn't excuse the small cache]
• jellyfin server is running (using GPU) on a gaming PC which is not nearly at 100% while streaming.
• I can see on the video seek bar that the buffered amount is 1). very small, and 2). it's not increasing as the playback goes through it until it hits the end and chokes, then another small chunk gets downloaded, and repeat. If I pause it doesn't stream ahead.

Cache size wise, from a programming standpoint, should be just about exposing an existing number for an upper limit. (the only limitation's maybe some browser client cache limits, which are definitely not being hit now).

There seems to be no clear or recent documentation on this:

• This old reddit post says "Go to Client Settings and change the option under Cache." But I can't find "Cache" anywhere in any settings. Where is the "Client Settings" button? I looked in Playback, Transconding, Streaming, (wtf is) Trickplay(?), etc.
• This jellyfin forum post gives some weird code location ~ ^/web/htmlVideoPlayer-plugin.[0-9a-z]+.chunk.js$ { What, do I put this in a greasemonkey script?