I’d recommend the work by Aiden Nichols “There is No Rose: The Mariology of the Catholic Church”
https://www.amazon.com/There-No-Rose-Mariology-Catholic/dp/1451484461
Read some of the reviews on the product page that give a good synopsis of the book and give a glimpse into how profound Mary’s role is as co-redemptrix.
I do not think that Christianity can be understood without Mary.