Mate, the intensity and the football played by Brentford in those season compared to what DCL was working with - one cannot compare.
I'm not sure how much stock you put in xG & chance creation stats but Brentford's numbers weren't too dissimilar to ours across the two seasons 22-24.
Everton's xG suggests we should've scored 109.4 goals across that period and we actually scored 74 goals.
Brentford xG suggests they should've scored 123.5 goals across that period and they actually scored 114.
The 74 goals we've scored across the last two seasons makes us comfortably the worst performing attack of any team to have participated in both of those seasons. Only Sheffield United scored fewer last season and only Wolves scored fewer in 22/23.
In any case, it suggest DCL has played in teams that create chances. In terms of xG we've created more than Fulham, Wolves & Palace across the last two seasons and created a similar number of chances to Brighton, West Ham and Man Utd last season. He should be doing better.