I really like studyquill which imo is Ruby's 'dark side of the moon' lol. She's a studytuber and very academic oriented but she also seems like a very well balanced young woman with lots of different interests and talents. I also watch AmandaRachLee for the bullet journal content. I'm not artistic enough to have my own bullet journal but I enjoy watching other people lol
For Booktubers I watch BooksandLala a lot, her videos are really fun and well put together, she always reads sort of niche books that not many people are talking about, and she seems like a cool, down to earth person. She's like 35 I think and has a husband and child. I also like Mina Reads and fictionalfates.
And then for slow living/cottage core we have annika's leaf, Viktoria Terekhina (she's not really cottage core, has more of a minimalist vibe. She's a Russian woman who recently moved to Georgia I think and is now living in the countryside with her husband and toddler), TheCottageFairy, PrettyShepherd, Karolina Zebrowska and Bernadette Banner for the more fashion-oriented content.
Hope this helps