The "culture over all" recipe also worked last year because Clemson was down. If Trevor Lawrence (a 5 star recruit) decided to come back for a senior year, we probably weren't winning the ACC. Heck, we probably would have had an extra regular season loss and would not have even won the Coastal.
That's exactly what concerns me. Our defense has been "ACC good" for a while, and I'm not underselling that. But the next step to becoming a national player is getting even better players. If I go back and look at Narduzzi's history against nationally-relevant teams, the defense hasn't shown up nearly as effectively. 2020 (52 against Clemson and 45 against Notre Dame... can't recall if all the points surrendered were defensively, but both teams could have gotten to damn near 100 if they wanted to) being the most recent example.