Man, I had seriously forgotten that episode 11 ended in that backstabbing cliffhanger, so a pleasant surprise when I began episode 12.
Agree with most of what you say, though I thought it was good from an entertainment standpoint... but yeah, those details deterred the enjoyment a bit.
I will add though, with one more episode to go, I'm lamenting that we didn't manage to get into a reveal and consequences portion with Iris. At this point I just hope she remains quiet and keeps going business as usual because there's really no time to treat that story point with any level of adequacy.
But yeah, time for Iris to overcome her yips and save Nagisa in spectacular fashion. Or die trying of course.