Why was Yumi able to change for Yuki, but not for Masachika?

Yumi started out as a good parent, but her resentment of Masachika turned her cold and distant despite loving him. She ends up lashing out at him, causing him suffering and making him leave the Suou house, which she feels immense sadness and guilt about. Yet, as Yuki herself was being raised, Yumi became a good parent towards her and changed somewhat as a parent. She supported Yuki even through Yuki’s struggles as the Suou heir. So why was she able to change for Yuki and not for Masachika? She had many opportunities to contact him and reconnect with him through Ayano, Koutarou, Yuki, etc. Why couldn’t she have changed to a good parent towards Masachika and fix their relationship?