How do they reinforce or undermine stereotypical views of mother-daughter relationships?

I’m not quite sure who the “they” you are referring to are, but I can discuss stereotypes of mother-daughter relationships.
First, it is important to note that psychologists consider mother-daughter relationships to be the strongest of all parent-child relationships, according to the Journal of Neuroscience. Mothers generally can empathize better with their daughters because many women have been through similar female experiences and can put themselves in their daughters' shoes.
Obviously, an extremely strong and empathetic bond between mother and daughter is what most would consider to be a best-case scenario, but there may be many configurations of the mother-daughter relationship. A common stereotype is the mother who tries to be her daughter’s best friend. Although this type of relationship can be beneficial later on in life once the daughter is an adult, it can be problematic while she is still a minor. The mom’s strong desire to be a friend and be seen as “cool” may actually cause a lack of boundaries and parental guidance. This stereotype can also manifest itself when the mother acts like a child or teen, requiring the daughter to take the role of the “parent.”
Another stereotype is the over-controlling mother who probably means well but is overbearing. This can lead the daughter to have issues stemming from the mother’s critical statements and treatment. The mom, on the other hand, believes the daughter is hard-headed and is making poor choices; she cannot understand why her daughter won’t take her advice. This is probably where the old adage “Mother knows best” comes from. The daughter wants freedom and to be treated like an adult, while the mother just wants to feel like her daughter values and makes time for her.
Finally, a third stereotype is the one of a mother-daughter self-fulfilling prophecy. This can occur when the mother has mental health issues, substance abuse problems, or has been abused. Since mental health problems and substance abuse can be hereditary, at times daughters find themselves in similar positions as their mothers once were. They feel doomed to make the same mistakes and may blame their mother as a result. The mother may 1) feel guilt for her daughter’s predicaments and choices or 2) be unable to understand why the daughter cannot learn from the mistakes of the mother.
Ultimately, mom-daughter relationships are not monolithic. They may have certain aspects of all of the above described stereotypes or may fall into a completely different mother-daughter relationship configuration. Finally, most mother-daughter relationships change throughout time, so no one label or stereotype would apply to all relationships permanently.
Works Cited
Yamagata, B. et al. "Female-Specific Intergenerational Transmission Patterns Of The Human Corticolimbic Circuitry". Journal Of Neuroscience, vol 36, no. 4, 2016, pp. 1254-1260. Society For Neuroscience, doi:10.1523/jneurosci.4974-14.2016.