I believe you are correct. I sailed on 4 different cruise lines including Princess since March. They all had over 100 songs in the karaoke song books. But the song selections vary and likely at the discretion of the person in charge. On this particular cruise, the karaoke DJ was from Mexico and 1/4 of the featured songs were either in Spanish or Mexican hits. The list even included a Santana instrumental hit Samba Pa Ti which is a all guitar solo song with no singing. Go figure.
Since October, I notice karaoke DJs have all stopped wiping down the mic after each use. This to me is a poor decision given all the singers are holding the mic 2 inches from their lips and spraying droplets all over the mic while singing into it, then pass the device to the next person to repeat the same process. That's when I stopped going to karaoke nights. Just not worth the risk of catching Covid or flu bugs from an unsanitized shared mic.