the most fundamental thing you can do to find success in any vocation so I've focused on it with my kids over everything else. Two things I would suggest.

1. Get an Alexa dot for their room and get a handful of books you choose with them that they can listen to when they go to bed.
2. I tell my kids that I will buy whatever books they want, every time. They never need to buy them. And I make sure that each kid had a book they were reading, even if it was Dog Man or other comic novels or even nonfiction fact books. Typically with kids who are behind they either like fact books (Guiness book of records are fun, or kid biographies) or they like comic style novels. Get whatever they want and just get them reading. If you want a great book that the vast majority of kids like, try the Great Brain Books. They are amazing for multiple reasons.