Very small sample size and is only one example, but across a 2 season simulation in the Championship on full detail.
Average Goals per Game IRL 20/21: 2.31
Average Goals per Game IRL 21/22: 2.50
Average Goals per Game IRL 22/23: 2.42
Average Goals per Game IRL 23/34: 2.83
Total Avg across 4 seasons: 2.51
FM Example Season 1: 3.26
FM Example Season 2: 3.30
FM Example Season 3: 3.62
FM Example Season 4: 3.47
Total Avg across 4 seasons: 3.41
Differential: +0.90
Goals maybe slightly on the high side. Know it doesn't sound like much, but when you consider that its a GPG it's a considerable amount (as it stands an average of 0.75 GPG when comparing to IRL, if my maths is correct thats +310 goals over a season) when other a full season. Maybe some slight tweaking needed, but as mentioned small sample size and just one league.