"What about me?" "Was it fun lying to your friends?" etc. - This does not at all read as somebody acting out of worry and genuine concern, but somebody acting out of spite and with a false sense of ownership over another person. It's not about Remu's wellbeing - it's all just about Niji, and what she wants or thinks she deserves.
Agreed, Niji's concerns about Remu all seem to be related to her fantasies, she doesn't care about the person, she cares about the character inside her head that Remu should be. And while I think there's some sympathy to be had for Niji, I won't excuse her blackmailing Remu.
On a happier (? note, I'm really proud about Azuki and how she has managed to overcome her trauma a bit. Also, Meguru feeling frustrated despite Azuki behaving exactly how she wanted her to be is hilarious.
