If she's the only giant in the world, then it's one of those stories where she deals with the advantages and disadvantages of her condition while worrying if she can live the normal life she probably wants. It's a pretty classic formula- take the usual expected romcom format and twist one thing. Also requires more restraint because, y'know, when you have a giantess fetish you'd obviously want to draw more than one. But that restraint rewards the story with more unique focus on its central character and her struggles.
The story as-is doesn't really hit this mark because it's so casual about everything. I think that's a funny choice itself and makes for a pretty breezy read, but admittedly it
should be strange that she's a giant. Handwaving it reduces the amount of free content for chapters and story arcs. They don't even have to be more dramatic in tone, just any kind of inconvenience or challenge for her in general feels missing. All the conflict is character-driven currently, which is a really weird thing when there's the literal elephant in the room of "giantesses exist."
Opposite that, if there are many giants then it becomes a Romeo & Juliet type romance about people falling in love despite their differences / belonging to different "cultures" I guess. This one introduces so many more possibilities for the setting IMO. You can keep the growth a random aberration or make it something people are born with (depending on how long you want to them to have existed in-story). If giants are a recent development, are they welcome and accommodated or is society still struggling with their existence? Would it be unusual for humans and giants to fall in love? If it is, then the protagonists are both outcasts, and if not, then you either have competition like in any other romance, or just focus on the obvious issues giants introduce to the typical trials of love. It also allows for more supporting characters from each protagonist's group, helping them, relating to them, or challenging them. And with this option, the artist gets to draw
many giantesses, which we like, because giantess fetish is the reason this manga exists at all. Hell, you could even feature multiple pairings. I'm now imagining a sukeban giantess and I need a moment...
I feel like I can imagine exactly how either of these manga would work... I feel like I've
read manga conceptually similar to both. And I don't mean to suggest any of these changes would definitely make the manga "better" - I'm just surprised the author settled on such an unusual middle ground when something more extreme feels like the obvious choice.
All that said, I found a picture on Pixiv of the guy waist deep inside her, so 10/10