agree with your take.
They couldn't be this popular if they are untalented. Are they the best singers? Rappers? Dancers? No, but they don't have to be. They don't have to be Adele or Celine Dion to be called talented. Taylor swift isn't a great vocalist but you certainly can't call her untalented.
I know that blinks might attack me but as someone who is neutral on them, who don't know entire discography, and who only watches performances of songs that i like, I don't see what jisoo brings on stage. She might have great personality and people like her visual but for me her not being part of the group wouldn't change a thing.