I guess Alvarez may play wide also, but think we need a natural winger as well to contribute who can score 15+ goals to support Haaland.Foden and Kovacic along with McAtee are adequate replacement for Gundogan centrally. Mahrez ball control and, like you said, output is really hard to replace… yet he must be replaced properly
Bernardo 7 goals in 55 games
Grealish 5 goals in 50 games
Its a corcern and as you say we just have to get any replacement right