If you like that UI you should check out Jellyfin.
I'm really bummed about Plex, as I'm sure many are, i was a very early lifetime supporter. I suppose I've gotten my money's worth but every update seems to somehow feel less functional.
I appreciate their trying to integrate the atari games, but I'd rather they cleaned up the interface a bit and squashed the long list of chromecast bugs they have open.
Still loyal but like other of the others commentators said, emby is catching up.
You can try using Plex for Kodi. I personally like its interface. Its even better if u use jellyfin because u can load the jellyfin server directly into kodi library. Then u have complete control over look and feel by using skins.
Think it was the Microsoft Store version some time ago
That's way old