daredevil I think those two are demons when it comes to tracking back but Trossard does get back, not with the same vigour as the Martinelli/Saka but he doesn't slack.
Klaus You are right about his drop off, I casually watch Milan time to time and he doesn't seem the same player he was. Milan on and off the pitch have been a shambles as well which probably doesn't help the situation.
I think we need that kind of wildcard in our team, we have Saka, Martinelli, Odegaard, Trossard, Havertz + hopefully a new CF so we have plenty of attacking threat there. We need that maverick who will do something out of nothing. Against Bayern last year and PSG this season we missed that, someone who thrives in those games and will elevate the team. The club will have watched him more closely but like you say, on his day he is the best LW in the world. It is whether finding out why he can't hit those levels consistently enough, is it due to the environment he is in or just his personality.
If not him I really like Nico Williams and Gittens. Gittens is probably quite raw but think he will really explode soon. I think we need the type of wide player who will take on their man aggressively. Unfortunately looks like Nico Williams is joining Barca.