I have no objection to romantasy as a category. None. The problem is when the “fantasy” part turns out to be decorative wallpaper behind two hot people glaring at each other.
The books that actually stick are the ones where the world has weight. Politics matter. Magic has consequences. Geography changes what characters can do. Desire has something larger to collide with.
That is why books like The Cruel Prince still work for me. The romance is sharp, but the court is sharper. Everyone wants something beyond each other, which makes the attraction feel dangerous instead of prepackaged.
Same reason I have more patience for romances inside real fantasy systems than for generic kingdoms with three made-up nouns and a cursed prince. The setting should feel like it existed before the flirting started.
Romantasy can be great. I just want the fantasy to show up in full costume, not as an excuse for the cover art.