Folders on Roku App

[paulc]

Spit balling here but IF Jellyfin Roku is displaying differently than when you view Jellyfin on the web, it could be you have the "Use Web Client's interface..." disabled. Open Jellyfin Roku, press asterisk to go into settings, chose User interface and then General and then Web interface and enable. I believe that is the structure for settings, if not browser your settings.

If that isn't it, it could be you need to adjust the way it is displayed by going to your profile's preference (clicking your user icon right hand top) on Jellyfin Web then Home and adjust your view preferences as pictured below

In my directory, all the tv episodes are in a single folder, but this is not reflected on the app.

As in every episode for every TV series is in the same folder?  Not subdivided so that each show has its own folder?
Also, what library type is it?  Shows?
Can you provide full file path examples?

As for anything else, I am with TheDreadPirate's reply. Ijust don't have enough info as to how you have things setup.