Yes, they own many companies that debut and produce groups.
And of course Kakao contributed to the success of these companies. They own part of Starship and StayC's company. To get ownership, they inject money, get on the Board, and decide what happens in the company. Regarding Cube, which they don't even own them, Kakao is giving them $60 million USD won over 5 years for the distribution rights. This is money other small companies don't have access to, to help produce and market their groups.
Cube has (G)I-DLE who were doing well even before the Kakao deal. They also have Lightsum who are flopping and not benefitting from that $60 mil.