Given the purpose and tone of the poem, what is the most accurate paraphrase for the title "Eros Turannos"?

The simplest translation would be "Love the king." In ancient Greek, turannos could mean both king and tyrant. Indeed, Greeks often made no distinction between the two—not surprising given the predilection for democracy in most parts of the Hellenic world. Given the thematic content of the poem, "Love the king/tyrant" seems an apt choice of title. It would appear that we're dealing with a woman in a codependent relationship; the love she has for her husband is one that comes to exercise tyranny over her.
She went into the relationship with so many romantic fantasies, of wanting to find her Prince Charming, so to speak. At first, that's how it seemed; but an "engaging mask" is still a mask, and the woman of the poem has discovered too late that the man she wanted is more tyrant than king. Yet for all that she still harbors the consoling thought, common among many codependent people, that she can still somehow change her husband's ways, get him to return to that blessed state which initially attracted her in the first place. But a leopard cannot change its spots, and a tyrant king will always remain a tyrant.
https://www.poetryfoundation.org/poetrymagazine/poems/12839/eros-turannos