I think the Bundesliga is a difficult league to judge players on. Even Batshuayi managed to look quality. Far as I'm concerned, most Bundesliga fans don't rate Andre Silva. (penalty merchant as well)
Tammy has proven himself in arguably the most difficult league in the world. People tend to criticise his overall game, but at Dortmund he would be at the focal point of so many creative outlets. You just have to look at Haaland's metrics and see how little involved he needs to be in the build up. I've always been adamant that when you have Tammy in front of goal, he will likely find the ball in the back of the net. He can only get better and on a team like Dortmund, in a league that provides so much space for attackers, I think he would absolutely flourish. Far more than Silva.
Personal opinion obviously.