It's the job of the manager to create chances that the team can score from. Burnley did not have much quality in attack in the 2018/19 and 2019/20 seasons; yet have more goals per game than Brighton this season.Brighton create more chances than all those teams so what's your point?
Leeds are 9th with 50 goals this season, Burnley 17th with 33 goals. Are Leeds' players really that much better?
xG is alright when analysing strikers, but should not be used to excuse mangers. xG does not take into account the amount of space a player is in when they shoot. The job of the manager is not just to create xG, but to build patterns of play that will result in higher xG to goal conversion.