How do I access an old iTunes library in Catalaina?

Hello, I recently upgraded from Sienna to Catalina on my late 2013, 27" iMac. In Sienna, I had 2 iTunes Music libraries. (Both on an external drive because they were too large for my iMac's internal drive.) Mine and my wife's. After upgrading, the music app aded all my iTunes music, but there's no sign of the hundreds of playlists I created. Furthermore, I tried to access my wife's iTunes library by holding down the option key as usual. I then selected her library, but the "open" button is grayed out. Can anyone please help with this? Thanks