I originally setup Plex and was immediately unhapy with their always online model as well as really poor support on their forums.
Pretty quickly moved to Emby and have been happy since (7 years). It’s not FOSS but it’s not locked down nearly as much as Plex, and they have a focus on keeping your info within your own systems. No telemetry.
I don’t mind paying a bit to support development, especially when they offer lifetime options instead of being stuck with a monthly subscription.
Jellyfin has branched out more into niche features like watch parties, leaaving some stability to be desired. Especially with apps like smart TVs. Emby has focused more on its core reliability across all platforms, comming up with a product that’s nice and stable pretty much everywhere.
Jellyfin was a fork of Emby when Emby went closed source as users kept removing the paywalls for premium features. Development time isn’t free; that’s not sustainable for a fulltime dev. Since, Jellyfin has barely kept up, lacking the resources/funding to really flesh out their code. (hell, ~75% is still embys code AFAIK)