I can't believe someone else remember this movie!! I thought the exact same thing.
Maybe like the film it would be better for them not to know each other?
Not really I think, Sora was suffering from before meeting Hinata, knowing that now he won't let it continue, I think best case scenario is making sure Sora grows up with a different family but our protagonist now also wants to save the people that will be hurt by crazy teacher so no single action solution.
About the butterfly effect movie
It's an older movie I think most people here weren't even born when it came out
It's also kinda of a bad movie in my opinion but a reference for works that have this time travel changing the future theme
Another work similar would be "life is strange"
Actually it kinda has a similar vibe to this with the missing person who was dead etc etc not that similar but a little lol
Also you noticed that even though they didn't name it yet as a "butterfly effect" there's a moment that MC was painting butterflies I was like "is this foreshadowing?"
It's like the movie butterfly effect but without the disgusting stereotypes instead of characters and the protagonist actually makes progress when he regresses