Her actions and policies aren't well-publicized, but they're not good.
As a simple example: in 2017, DeVos and Trump proposed "cutting $1.2 billion for after-school programs that serve 1.6 million children, most of whom are poor, and $2.1 billion for teacher training and class-size reduction" [1]. These cuts also affected efforts such as mentoring, recruitment, and retention [2].
In 2018, she proposed regulations that "require full hearings, cross examination of sexual assault victims, and raise the standard of evidence to hold a student accused of sexual assault accountable" [3], which experts have said "would allow schools and the Department of Education’s Office of Civil Rights to ignore much of the sexual harassment that occurs in schools" [3].
I don't even know how to summarize this whole mess, so I'm just going to use the subtitle of the article: "The administration wants to keep schools safe by ditching rules meant to prevent racial bias in school discipline" [4].
More recently, she "illegally delayed an Obama-era rule that required states to address racial disparities in special education programs" [5].
[1]: https://www.washingtonpost.com/local/education/trumps-first-...
[2]: http://www.nea.org/assets/docs/Funding-the-Wall-vs-ESEA-Titl...
[3]: https://www.thedp.com/article/2018/11/betsy-devos-education-...
[4]: https://www.theatlantic.com/education/archive/2018/12/trumps...
[5]: https://www.nytimes.com/2019/03/08/us/politics/betsy-devos-s...