Must I continue my engagement to a girl who is very materialistic, is influenced by the words of her female relatives, pushes me to compare myself to others, and does not adhere to some Islamic teachings, especially since I am going through financial hardship?

A marital life is founded on religion and good character. If your fiancée accepts wearing the niqab and that it be concealing, then invite her to steadfastness. If she responds, do not break off the engagement. Otherwise, it is better to break off the engagement, as it is easier than a marriage that may lead to discord and divorce. Breaking off an engagement is permissible, especially if there is a reason for it, and it is disliked if there is no acceptable reason. If marriage becomes easy, then praise be to Allah. If it does not, then cut off all ties with her and repent to Allah, for speaking to a non-mahram woman is not permissible except out of necessity, and an engaged woman is a non-mahram to her fiancé until the marriage contract is concluded.