A convenient model category for bicategories

We introduce and study the model category of flexible $2$-categories, which is Quillen equivalent to Lack's model category of $2$-categories, but enjoys several excellent properties not shared by the latter. In particular, every object of this model category is cofibrant, it is a monoidal model category with respect to its cartesian closed structure, and its full subcategory of fibrant objects is equivalent to the category of bicategories and normal pseudofunctors.