You can't separate defence and offence into distinct categories like that.
We aren't a side that loses slugging contests where both sides attack and the best wins. We lose games when we concede a goal against a side who then successfully parks the bus, and usually we concede those goals because the attack is not working first, which builds pressure, and we over commit trying to force a goal.
If you bumped up our efficiency in front of goal 10%, we'd concede 10 fewer goals, easily.
Because time after time, we miss buckets of good chances, panic, and then concede a stupid goal on the break because we're desperate to score or else we'll fall behind in the table.