Does Frames blur the edges of my image?

No, and that is deliberate. A real blur creates semi-transparent pixels, and those are exactly what causes white haze on a DTF transfer. Frames dissolves instead: the edge breaks up into grit, halftone dots, or scallops. At arm's length it reads as a soft, blended fade, but every pixel stays fully opaque or fully transparent, so it prints clean. If you want a genuinely soft edge for sublimation or UV printing where haze is not a concern, use Frames in Overlay mode instead of Erase.