That is very true, and exactly what I just wrote when I said if you do it over years you are not lucky, you are consistent. But this has nothing to do with Vlahovic since he has not broken record after record, or done it for years, he has broken one record, mostly because of a stunning return this first half of the season and a huge number of pens. Its only this season he has over-performed by some noticeable extent. He has scored 10 non-penalty goals from a npxG of 5.71. The over performance is with other words like you said "very little goals". Last year he scored 15 non-penalty goals in 37 games, and did not over-perform his numbers even close to what he is doing this season. Which shows he is a great young striker, but not exactly Haaland level. But when you combine 4-5 goals over-performance in xG this season, with a goal every third game from a penalty (10 in total this calendar year), that's all of a sudden 15 goals out of the record 33.
But like I said, I think he is a good striker, and that he would be a great option for us. And his ability to score penalties is something that could come in handy considering we are not exactly clinical in that department. Im just saying that his current numbers are a bit inflated by a 75% unsustainable over-performance in xG (25-50% is considered elite) this season and a huge number of pens.