Well that’s why I see it.
I find him quite a calm and composed player which actually makes him easier to read as a winger because he shows no tenacity.
As a false 9 he plays just deep off the central defenders where the defenders will be coming out of position to take the ball away from him.
At that point he doesn’t have to show any tenacity or speed, just be calm and composed to trick the defender ( he has done this against Liverpool, Leicester and Fulham) and just focus on the final finish or pass - which is what he always did in the Bundesliga.
He never made the pre- assist to assist to assist, he always made the final assist and finish - that’s what made him so good in the Bundesliga with ridiculous stats because he would routinely break the high line and make the last calm and composed pass or finish.
In the PL the high line is not there, the closest thing to that is playing as a false 9 and let the defence come forward to get the ball off you.
Then he has to make the final pass, run to beat the higher line caused by the pressing central defenders or make the final shot himself.
Rashford - Greenwood
Sancho
Sancho as a hybrid CF/False 9 is the only future I see for him here playing between two deadly inverted forwards.
He is not good enough or creative enough to play as a CAM from deep and he is not good enough as a winger because he can’t take on his fullback.