Hi there, A1ps.
After reading your post, it appears that songs in your iTunes Library aren't syncing to your iPad. There's 500 songs (give or take) in your iTunes Library but your iPad is only showing 5. We're glad to help with this.
Change where your iTunes files are stored on Mac -- If you're not seeing any of your songs in your iTunes Library and you've relocated the library, the steps under "Change where imported files are stored" to confirm it's pointing to the correct location of your songs.
Use iTunes to sync your iPhone, iPad, or iPod with your computer -- If you're seeing all of your songs in the iTunes Library, make sure that "Entire music library" is turned on. If you don't wish the entire library be added to your iPad and "Selected playlists, artists, albums, and genres" is selected, select what you'd like added to your iPad. You're not limited to only playlists, artists, albums, and genres, you can select each song individually.
Use the Finder to sync your iPhone, iPad, or iPod with your computer -- If you've upgraded your Mac to macOS Catalina, you'll use Finder to sync now.
What happened to iTunes? -- With macOS Catalina installed, there's been a few changes. This article explains what happened to iTunes after upgrading.
Let us know how that goes.
Take care.