To be fair I think you've clarified the question yourself.I don't know what article your referring to but that would require alot more clarification.
Of course, if your scoring a high volume of goals, then if you under perform your xG then who cares, your scoring loads anyways.
But up to a certain point, you can't be under performing this metric all the time. The best strikers like Lewandowski who have huge volume goals, who does underperform his xG, is still at around 99%.
Mbappe, Haaland, Benzema all over 100% AND have high volume to combine with it.
Jesus is clearly able to get in good situations, his xG/90 is the best in the entire squad since his time here (0.73), this number rivals some of the best strikers in europe, the lad is very good at getting in goal situations (perhaps aided by how we play), but he has struggled to convert them to then match the best strikers in europe.
If he reached Sterling levels of conversion (or even better) we would probably be having an entire other conversation about him and talks about him would be about how we might have one of the best strikers on the planet.
He's not a player who has everything, but the stats suggest he excels at getting into dangerous positions, or creating big chances for himself, but isn't the best finisher. A player who exceeds his xG might be the opposite - almost totally relying on service. The very best, Mbappe, Haaland, Benzema, excel at both.
Jesus, despite taking few penalties, has the best per minute scoring ratio in the squad by some distance, so, as you said, a slightly better finisher, and he'd be up there with the superstars you mentioned.