First of all, thanks for sharing, second, your game looks very good, it has a premise that, although it is not original, does not mean that it cannot be excellent, so good luck.
As for the sandbox part, many don't like this because of its repetitiveness, "go with a girl, talk to her, earn 100 points and then watch a cutscene, and so on with all of them", so I would recommend that, if you are going to insert sandbox, either as summertime saga or as milf city, that is, without "affection points" and directly to the scenes, that helps users not get bored, additionally inserting things like jobs or skill improvement can help to be entertaining.
Regarding the "possible" (although I hope unlikely) "share" content (if you don't really think of putting this content, please ignore this part), I recommend that it be according to the story, that is, if the MC is dominant and is going to to have his harem, the most logical thing is that, if he puts something in, it is more like a trio or something like that (MC, ally of the MC and girl), this to have coherence with the plot, since someone appears and steals his girls to the MC (optional or not) just would not be consistent, this is just a suggestion.
Taking all of the above into account, I think your game has a lot of power, I wish you luck and they were only suggestions, I hope they are not taken the wrong way.