I was like you when I migrated from kodi, and i figured out pretty quickly that I'm not saving myself any work by going with a paid program. JRiver does a few things better than kodi but you will have to read up, and see how the software works, like any other program. To answer a few of your questions,
1.)Like Kodi, JRiver stores all the info for a file in that file's folder so, I have a folder for each media file. In JRiver, find the file you want, right click and press get Movie and TV info. This will bring up a box that asks you what database you want to use. Pick your database, and JRiver finds your cover art and description.
2.) JRiver is famous for its tagging abilities. Instead of naming the tv shows after episdoes or seasons, if I'm reading your post right, try using tags instead. There are quite a few different tag fields including, season numbers, episode numbers media types, and media subtypes. I bring up Media sub type tags because they determine whether your file will be displayed as a movie, or a TV show.
JRiver takes almost as much work as Kodi, and like their forums, you have to ask informed questions. Good luck, I hope I answered your questions.