I used Kodi for around 3 years (on LibreELEC and standalone on various computers). I would recommend going through the settings of Kodi and any addon you install as there are a lot of things you can tweak. In my experience, most good looking skins/themes made Kodi too slow to use (and take a while to setup). I mostly used Kodi to stream using the Fen addon, so I just configured it to open automatically when starting Kodi.
I would give more specific recommendations but I haven’t used Kodi in around a year at this point and Kodi-related projects have a tendency to get abandoned/disappear; I’m pretty sure Fen was taken down since I last used it, for example.