> By the way, I don't think there is anyone homeschooling with the "only textbook is the Bible"

They’re pretty common, in fact. Here’s a curriculum company that’ll gladly give you the tools: https://answersingenesis.org/homeschool-edition/

“The Bible is the only education you need” is a very common meme among evangelical Christians.

> and in most states you need to file a curriculum every year that gets reviewed and approved.

Most states have almost no recourse to reject submitted curricula, no matter how specious they are. One influential homeschool association has a 24/7 legal hotline specifically for subverting these mild attempts at accountability.