Not sure how I can explain this best. When connecting to my NAS through PLEX via my PS4 media server browser or even my smart TV for that matter, I have to navigate through like 4 or 5 sub folders to get to my movies/pictures/music that I have saved on my NAS. When browsing the same NAS through the built in Synology media browser via PS4 I don’t have to navigate through all of those folders to get where I want. I just select movies/tv/music/pictures. I hope this makes sense. I love using PLEX because it allows for thumbnails to show on my PS4 but the subdirectory navigation is cumbersome.
Just for clarification… Are you using the native Plex app on your Playstation or are you accessing Plex through DLNA from another app (e.g. the PS4’s native videos app)?
Edit: native Plex app should at least be available on the PS4; PS3 is probably no longer supported.
The native apps should act just as what you’re looking for. You cannot edit the folder structure presented via DLNA; this is supposed to give you at least a minimum level of options on how to access your media (e.g. by decade or other groupings).