Don't read it if you want. But please stop spouting the first assumption you have when you really don't know anything.How about I don't read the entire manga and ignore you till you post something with some actual content rather than some nonsense.
1. Clown suit metaphor for an idiot in suit running around failing at shit is... False? What does that even mean, did she want to fail at murdering, was she forced to wear the outfit? If you're so invested in telling me I'm wrong, why do you make negative effort to not explain why.
2. "No but actually if you go read this stuff you'll understand how the character is actually smart for doing this stupid thing".
If it's so smart why cant you say why it is smart rather than telling me it's a "plan" or "you don't know because you didn't read".
A plan that includes a staggeringly high chance of being outright murdered is not a good plan unless your goal is to get murdered.
3. As I explained earlier, the author picking the 1 out of a multitude of options that is clearly the only option that benefits the opposite character... To take your chess nonsense, the player can move a bishop in 4 directions, 1 of these directions directly benefit the opposing player, now nobody would move their piece in this direction normally BUT, here we have author with the ability to force the player to do this losing move, this is a an example of "plot armor".
Not to mention that the "player" seems to be heavily motivated to do the instantly winning move but just doesn't because who knows, but it sure as hell doesn't make sense to me for someone in an angry murderous mindset to listen to their opponents solo talk for a minute or more while knowing they are limited in time and at the scene of a recent "unrelated" murder "attempt" (she should be dead, they should all be dead). It's like pausing for a transformation scene in a transformers/magical girl setting or the bad guy revealing their master plan to the main character letting the main character slip away safely because of the wasted time, it's a dumb plot armor device.
It's the last time that I will do that (giving information that you would knew, if you read the previous chapters):
1) She didn't want to kill them because it's not a murder story but more like a vengeance/mind corruption type of story. If you want to know more read the story.
2) The manga is actually 19 chapter. I will not resume when the story isn't that long to read. Personally, I found that the plan was clever but it's only my opinion. Make yours when you know the plan.
3) In chess, the closer we get to the endgame, the lesser choice you have. In this case, you saw the endgame unfold and judged that it was plot armor. For comparaison, it's like you saw a checkmate and said that the outcome of the game was decided before it begin, that they cheated.
In her situation, there was no winning move. Killing was not an option because she want to know something from this person.
Finally, people aren't robot. They have feelings and emotional baggage in addition to their motive. Yes, this is a plot but the outcome wasn't there only because the author wanted it and with bullshit explanation so... It isn't plot armor. But be my guest and read the manga and then explain me how it's plot armor. That way, we could have a meaningfull argument about this manga. Until then please take my advice, it would lead you to less biased opinion and allow you to discover more interesting story.