What are the steps one can take to avoid the unlawful (haram) and be blessed with a righteous wife, and does striving for this alter what is predestined and written, and how can one know their future provisions and overcome the fear of them not materializing or of being afflicted?

Provisions are in the hands of Allah, and they have been allotted and finalized, and inscribed in the Preserved Tablet. Therefore, there is no need to worry or fear about sustenance or the future. The servant's provision is predetermined and inscribed for him while he is in his mother's womb. What Allah Almighty has decreed will come to pass, whether you strive for it or not, and your striving or lack thereof is also decreed by Allah Almighty. Since the future is part of the unseen, it is impossible to know what Allah has decreed regarding provision. Hence, fear, anxiety, and laziness must be removed, and diligence in taking the means should be pursued.