Burton won automatic promotion the other year with something crazy like the fifteenth best attack, because they had the absolute best defence. The worst defence you’ll find to win automatic promotion in the last 7/8 seasons is about fourth. That says a lot.
Peterborough are the best example of a good defensive record being essential. They tried to swashbuckle their way to promotion for years and only actually got out when their defence was the fourth best last season. They were the league’s top scorers in 19/20 when the season was curtailed but their defence was around tenth, which is why they didn’t have the extra point or two that would’ve stopped the Wycombe PPG nonsense, as they couldn’t close enough games without scoring multiple times themselves. They missed out on the playoffs by one point in 18/19 because despite finishing seventh they had the thirteenth best defence, while the rest of the pack were all many places higher / better. In 17/18 they were the league’s third highest scorers but finished ninth, because their defence was the fourteenth best.
Most incredibly, in 15/16 they were actually the league’s joint top scorers with 83 goals, but didn’t even finish in the top half of the table, because they had the fourth worst defensive record after conceding 73.
You’re resigned to a playoff lottery at best unless you have a top five defensive record. That’s just how it is. You might get promoted that way, of course, but we have a manager who is becoming the best at losing in that regard, so the odds aren’t exactly favourable to that being the way to go. After two clean sheets in 15 games in all competitions this season, there is a lot of work to be done. Defending better or investing in a higher calibre of defender to begin with, rather than ploughing extra cash into a sixth winger, doesn’t mean having to be negative or ultra defensive.
Keep the goals out and top two is possible. Otherwise it’s playoffs at best before a ball has been kicked.