Sakura would likely become more confident. Standing up to Sasuke means she's no longer the meek girl who just follows him around. She'll start to trust her own judgment more.
Well, it could be that Sakura finally decides she's had enough of Sasuke's brooding and cold behavior. Maybe she stands up to him about his disregard for the village or his lack of communication with her. She might tell him that she's her own person and won't tolerate his dismissive attitude anymore.
Sukuna does die in the manga. The way it happens is quite dramatic and ties in with many other elements of the story, adding depth and tension to the overall narrative.
There's a great one called 'Sasuke's Utilization of Sakura'. Here, Sasuke uses Sakura's physical strength. Sakura has trained hard and become quite powerful. Sasuke pairs up with her in battles, and he uses her brute force along with his own skills to defeat enemies that are much stronger than them individually.
No. Ryomen Sukuna is a fictional character from Japanese mythology and modern manga/anime. He doesn't have a basis in a true historical event or person.
Nope. Ryomen Sukuna has no basis in reality. It's a product of the creative minds of the writers and illustrators who designed a captivating fictional character for the enjoyment of the audience.