Whut? There are people denying Those two? Where? They are litterally the least usemess lesbians, period.
It's hardly perfectly clear what their relationship is, other than "close". I've gone back and forth on it myself.
They are planning to live together even post graduation, and one of the really big ones for me is the Kasumi chapter about how she just loves to come home to Sakurakos smiling face.
Though it is an unconventional setup, it seems like Sakurako is afraid of refering about them as a couple for whatever reason, But the series is full of relationship milestones All the way down to the aprooval of both sides parents.