Others in the thread have pointed this out, but they did have a lite plan that wasn't rolled out broadly for some insane reason. They axed it this month:
https://www.theverge.com/2023/9/25/23889917/youtube-premium-...
https://www.theverge.com/2023/9/25/23889917/youtube-premium-...
Yet another one for the Google Graveyard collection, I guess.