Of course, it is just impossible that Madueke replaces Saka. Saka will be always the main option for the right winger, meanwhile Martinelli is the main player in the left winger. Madueke probably becomes the substituted player of these players only. Madueke must accept that he may not play regularly as the starter. He must already realize this condition before he accepted Arsenal offer.
Exactly, Madueke can't replace Saka. Saka is Arsenal's main player, one of the key players, and the brains of Arsenal's game. Indeed, their primary positions are both right wingers. However, Madueke's arrival at Arsenal has met with pros and cons from various parties, especially Arsenal fans. But on the other hand, Arteta's pushing for him.