oh the story is going to come slowly dont worry. But i also have fun writing side content - like that belle delphine. I still consider the game to be very early. People complained at the start when the felt the world was empty, so i populated the world with different content. The game is still very youngIts your game and totally up to you what you do. I would not count the prologue material towards your sandbox content. Firstly it was full of introductory material that really didn't develop character arcs. Secondly there was a huge word dump (not in a negative way, it was an important reconnecting plus evolution of way they saw each other scene but still something that happens in first week of MC's return) in Kiaras event that really didnt give a lot of information or push Kiaras arc so word count hardly a measure. The best guide is how many events or game days passed for each, yes Kiaras one event post sandbox was a lot more complex but it was all over 1 day. If you estimate 2 or 3 events per week per character some characters have a months timeline done while Kiara still not done half a week.
Keeping timelines in sink does not mean you have to add a lot more content. Kiara and MC could be avoiding each other trying to come to terms with dreams that night and the wake up incident so a couple of renders and short dialogues could fill in several weeks of timeline. A temporary barmaid at Pub will cover a gap in another timeline. Mother doing a location shoot. ETC ETC.
I really hope I not offended you because I do like your storytelling and the concept. I also like the subtle fantasy elements in modern setting. This is why I worried your not focused enough on telling your story. I still going to play and join your Patreon and will update my review once game has developed more. I have never seen a story told by a committee work.