Yeah, this assumption Malen is a wide player when he's not.
What is he then? He's not a direct replacement for Watkins anyway. Second striker perhaps and does give us that option against weaker opposition - Leeds, Burnley.
He's a striker. The one outstanding season in his career was at PSV when he was a centre-forward with Madueke and Gakpo supporting him. He got 27 goals as a 21 year old playing mainly through the middle.
That season was enough to make Dortmund want him as their eventual Haaland replacement, but then they kept on buying more and more other potential Haaland replacements (Haller, Modeste, Adeyemi, Fullkrug, Beier, Guirassy) so he never really got to play through the middle for them and was shunted wide. And wasn't particularly good there.
So it's not a massive surprise that he hasn't looked particularly impressive for us playing wide, but has done a perfectly capable job when asked to play centrally.