Is it obligatory for a wife to seek divorce from her husband who drinks alcohol, does not pray, blasphemes, insults her, and does not treat her as a wife should, especially since she fears for herself from deviation after performing Istikhara regarding divorce and becoming certain of her hatred for him?

If the husband, being sane and uncoerced, curses the Divine Essence, he has disbelieved and apostatized from Islam. His wife must separate from him and not allow him access to herself. If he repents and returns to Islam while she is still in her waiting period (iddah (definition)), she may return to him.

As for his abandonment of prayer, drinking alcohol, disliking the hijab (definition), and deserting the marital bed, these are major sins that make separation desirable, even if he did not curse the Divine Essence.