As long as you can buy goods, whether ordinary books or textbooks, as long as they are books, you can open a bookstore to sell them.
But the reality is often that the textbooks are basically monopolized by Xinhua Bookstore. This is the traditional business of Xinhua Bookstore. Xinhua Bookstore is responsible for distributing teaching materials, so as an individual bookstore, even if it wants to sell teaching materials, it is basically unlikely to squeeze into this basically monopolized market.