In Mikudashi Ibari wa Mikudashitai, Ibari becomes an egoist after being complimented by Yonekura (stylized as "gloomy"). He endeavored to go to the same school as her, only to be disappointed with her radical change in personality. He's outright disgusted by her for much of the serialization, and their "dynamic" involves her showing off to him in a bid to seduce him so that she can "look down on him". Meanwhile, he rejects her without hesitation and thereby embarrasses her-- the bulk of the work's comedy is derived from this irony of someone who seeks superiority being constantly and aggressively humiliated.
In this manga, Sorako is naturally an egoist, but more than that, a so-called "mesugaki" that takes digs at Kotaro (stylized as "average") and especially his masculinity as to provoke him (Ibari never did this with Yonekura). They're together because he was effectively sold to Mozu's family, and this further informs how Sorako typically treats him. She's far less "pitiful" than Ibari, managing to normally domineer Kotaro; her provactive acts are meant to tease, not necessarily seduce, and the comedy(?) of this work is in seeing how either party "wins" against the other. Generally, Kotaro is attracted to but annoyed by Sorako-- not disgusted.
I can see where the similarities are... if I step 200 feet away from the screen.
...and ignore that this manga came out before Mikudashi Ibari wa Mikudashitai.
I'm not even trying to gas this manga up-- I just don't care for lazy comparisons on the caliber of "these two manga have barely any similarities at all, they're practically the same". It's like when people claimed Seraph of the End was aping AOT just because they both had protagonists that wanted to kill an entire monster population-- it's silly.