I think by this point it's a generally safe assumption to say the only major difference that isn't a butterfly effect between the two timelines is Sou's willingness to have sex with the girls. Which would imply that Hinata has always had all of this inside of her, she's just significantly better at keeping it bottled up.
But that is why this story is wholesome, and the other is not. In the R18 version, Sou is honestly an asshole and he kinda exploits the girls into having sex. They are desperate after all.
Here he is kind (and oblivious, but whatever) and so they like him more and more.
This story -> the girls are starting to really LIKE and care for him
The R18 version -> the girls are basically all happy but... in truth he's sorta just using them.
Heck, in the R18 version he says more than once "I raped her" talking about various girls. Ask yourself how much of an asshole one has to be.... In the R18 version he's basically an NTR doujin protagonist, except there's no NTR cause he literally has no competition