Which is more preferable and important: to be deliberate and not rush into marrying someone weak in faith who might have a future negative influence, or to wait until someone who maintains his religious obligations and prayers proposes, given the risk of impatience and falling into prohibitions?

Since you fear falling into temptation, it is not permissible for you to reject the suitor. Marriage, in your case, becomes obligatory due to the necessity of safeguarding your chastity and diverting yourself from what is unlawful. Therefore, consider the best among those who propose to you, the one closest to religious piety and good character, and accept him as a husband. After marriage, be keen to cooperate with your husband in obedience to Allah, seek Allah's help, and supplicate frequently.