My understanding is that the Jellyfin team is working hard on the clients story. But yes, right now, the story is a bit lacking. Note that there are third-party alternatives that can fill the gap such as Infuse on iOS/tvOS.
We all know the workarounds and bypasses and the "pay infuse so you don't pay plex". But come on, it's a tacit admission that plex is on a better position: which is all the op said.