We don't play a stable defence as Pep has his fullbacks playing in midfield half the time,which suffocates the space there,and leaves us exposed to the counter attack.
This is more backwards, left is right, up is down stuff like your post about Ferran Torres' one footedness.
Playing a fullback in midfield is what made us almost impossible to counter in 2017-2019. the block of 2 in front of the back 3. Blocking the middle of the pitch, while leaving our LCB and Walker to mop up anything played into the channels.
What's happened since then is we've moved to having a normal LB with Gundogan or Bernardo dropping into the 2 and that's made us much, much weaker on the counter.