How can a woman decide whether to accept a suitor who is of good character, but is weak in prayer and Qur’an recitation, and has some objectionable behaviors and ways of dealing with her, especially since she desires a pious, knowledgeable husband who will help her in her religious devotion?

One should be deliberate in matters of marriage and pay attention to religious commitment and character. Prayer is the pillar of faith, and he who neglects it cannot be expected to know the rights of his wife. Similarly, one with behavioral issues should not be accepted unless he repents and reforms himself. If the family is unaware of his condition, they must be informed. You are not obliged to obey them if they insist on you marrying him. As for fear and overthinking, you should seek help from Allah and from people of virtue and wisdom. Any relationship with the suitor must be severed, as he is a stranger (non-mahram (definition)).