I feel like we're brushing past Besty Devos.
She's an "school choice" advocate. What this means is that she wants people to be able to choose between public schools and charter schools. Every now and again a "model" charter school gets paraded around for having better test scores than the public schools. However across the nation, consistently every year, charter schools always average worse test scores even than public schools. This is true if they're competing with underfunded poor schools or elite schools in richer areas, or anywhere in between. They always come up short. Furthermore charter schools frequently accept admissions via lottery; so unlike private schools they're not purely a playground of the rich, but on the other hand they are not a consistent answer for our education problems even if they were better (which they aren't).
Betsy Devos is even more toxic than that tho, because she believes that charter schools should receive government funding but not be bound by the regulations that apply public schools. I don't think it needs to be explained why this would be god awful.
On top of all that she's completely unqualified for the job. She's never been a teacher, she's never been a public school student, her kids aren't even attending public school. She doesn't understand the system she's about to have a lot of power over. I know since Trump won we've all become desensitized towards this but I want to emphasize that this is an important, fragile time for our school system. It is generally agreed, by Republicans and Democrats, that our school system is inadequate, unfair and uncompetitive with other countries, at a time when our economy relies on the highly educated. Many of our poor and our criminals never graduated high school, and in many cases they attended "dropout factories" with <10% graduation rates. Part of the reason the rural poor are so uneducated is because schools are funded via local taxes, causing a cycle of poverty where people who go to those schools have no hope of better employment. On top of that colleges (and some scholarships!) value applicants who took part in extracurricular activities, which is essentially code for whether you went to a rich school or not. Can't afford textbooks, you damn well can't afford a basketball court.
The political will exists for change in the school system, and people have tried to fix things, but it hasn't worked yet (which is a whole different wall of text). Betsy Devos' ideas are dangerous and foolish, her reaching her position with Republicans holding so many other positions is Bad News.
Edit:
This is a good example of her history and why her policies are bad.