The network they started on was going bankrupt during the 4th season. The show was planned out from the start to have 5 so they had to rush the overall planned story and pack 2 seasons into 1 for the fourth. Makes for a very exciting season and it's pulled off well and the finale should be treated as the series finale and is an absolute mind fuck, super thought provoking stuff. Anyway, put of the absolute blue during the end of season 4 production, TNT offered to pick them up so they had to scramble together a season 5 after the story was finished. It's not awful but I'd think of it as an epilogue.
I'd give it a rewatch. I've described it to friends as if ds9 had a child with The Wire and Uncle Dune came to visit on occasion.
Dunno what a jellyfin is, but best of luck. If torrents are your jam there's a super reliable public 360p version of the whole series available across pretty much all public places you'd find such. Doesn't take up much space and the quality is about the same as it would be for original broadcast anyway so I usually go that way for older shows.