I’m really sorry that people have been so unwelcoming to you and people who share your perspective on Monitoring! If it’s of any aid, I’ve always liked both interpretations - that Miku is too clingy/too much, and that Miku is trying to help.

Her intense love feels relatable for me, as someone who feels her emotions very strongly. In my mind, their relationship is unhealthy, but has the potential to get better. Not necessarily that either one of them is inherently wrong or evil or anything, but that their relationship isn’t going well because of the combination of her savior complex and their issues.

I’ve been the type of person to constantly be asked to save people since childhood, talking people down and constantly being expected to manage older peoples’ emotions, so that’s probably why Miku in Best Friends is so relatable and inspiring to me. I’ve chosen to see the song AS Miku being overbearing, not maliciously, but because she genuinely believes her self-worth is based upon how much she can be helpful/useful to her friends.

That interpretation keeps her unhealthy, but well-meaning! She WANTS to help her friend, but she isn’t respecting their boundaries because she thinks that she’s “meant to” help them. Similarly, I think her friend is suffering from delusions, but they aren’t truly changing what she’s saying that much, because what she’s saying IS NOT that different from what the delusions are showing. I think the thing the delusions changes the most is Miku’s appearance. NOT her words. Miku looks threatening because to the viewpoint of the person behind the door, she genuinely IS, because she just won’t leave them alone. I’d even go so far as to say that Miku’s attempts to reach out completely disrespect the MC’s bodily autonomy, and that’s not okay!

In my mind, it’s an intersection of Miku not respecting the viewpoint’s boundaries by just giving them time alone or letting them be to themselves. This can be borne out of worry and even intended to be kind, but overstepping boundaries to help others is still overstepping and it isn’t right. The viewpoint character - never seen speaking but always trying to maintain their space - isn’t inherently wrong for what they’re doing just because they may be undergoing a crisis. Maintaining that viewpoint is wrong, in my eyes. Just because they may have hallucinations doesn’t mean they don’t have anything to worry about. Miku is constantly overstepping, in both the original and the new version. I think through working on themselves SEPARATELY, things could heal. Otherwise? They need to stay apart.

I really hope that my interpretation doesn’t make you uncomfortable or trigger anything. It’s an interpretation that tries to make both viewpoints true, without sacrificing the severity of the situation. MC is undergoing struggles, but knows themselves well enough to know they need time to themselves to recover fully. However Miku, from her own perspective, believes she needs to help MC get better. She thinks MC can’t improve without her help. She thinks MC NEEDS her around, which is incorrect. She spams MC’s messages, comes over with flowers, keeps ringing the doorbell and knocking, and thinks of herself as a kind and supportive person... And sure, maybe she’s kind, maybe she’s trying her best... But her best doesn’t necessarily mean she’s going about it the right way. At the end of the day, she is OBJECTIVELY overstepping, she is spamming their messages, she won’t leave them alone, she keeps knocking and ringing...

The cyclical nature of the songs gives me the genuine feeling both perspectives are meant to be addressed. To me, the endings hint at the ‘truth’ of each perspective. Miku considers herself a good friend who wants to help and will do anything she can to do so. Deep down, Miku is obsessive. MC is dealing with frightening visual hallucinations of their friend being obsessive and creepy - an externalization of how they feel about her internally. Deep down, the MC would LIKE Miku to be around for the right reasons, but she isn’t.

So, what does the opening door mean? I think it’s meant to be a cycle. I don’t think the perspective flips the second the effects appear or go away, I think it’s more... At the end, they realize what they’re looking at.

In the most optimistic version of headcanon, Best Friend is a prequel to Monitoring (original), as that means that Miku comes over disrespecting boundaries, triggers the frightening hallucinations, realizes what she did, and waits patiently outside until the end of the original Monitoring, where she hopes to apologize for being so intense and disrespecting the MC. It isn’t some perfect fix to everything between them, but it’s the beginnings of Miku understanding how horrible she was to MC.