Made a little exercise with ChatGPT over good Serie B scorers, whose teams have been promoted to Serie A the next season and how the goal scoring have continued in A.
In the past 10 years, over all the top scorers of the 3 promoted teams each season, who have continued to then play in Serie A the next season, the ratio of goals in A vs B on average is 0.26.
For 26-year-olds and younger, the ratio is 0.20. I included arbitrary number 26 becuase Gyasi was 26 when he was at Spezia and got 0.44 ratio when they got promoted. So that number, if used with 25-year-olds, would have been even worse.
I don't know can we make anything out of this, maybe something, maybe nothing, but the fact is goal tally in A the next season is usually not even half of Serie B goals. And even worse if veterans are filtered out of the result.