I don't think I've misunderstood your post. I just think it's an offensively ignorant point to make. And I don't even know what it's supposed to be based on.
Stats ((G+A-PK)/90):
Bundesliga: Haller 0.69, Weghorst 0.59
Eredivisie: Haller 0.67, Weghorst 0.54
PL: Haller 0.31, Weghorst, 0.24
CL: Haller 1.20, Weghorst 0.00
EL: Haller 0.58, Weghorst 0.29
Five competitions they both played in, in every one Haller outperformed Weghorst. Haller got to play for bigger clubs, despite Weghorst being far from outpriced of a move in all those years, he won more titles, he fetched the bigger fees and he got the much higher evaluations from the halfwits of transfermarkt, his lifetime rating on whoscored is 7.37, to Weghorsts 6.99. Some of these metrics are jokes, but he's better in all of them. Not to mention if you actually were to watch players before you convince yourself you can compare them, you would have seen that Haller did so much more than just put out G/A, because his movement opened up the game for everyone around him - at least at Frankfurt and Dortmund.