Noni Madueke's arrival wasn't to replace Saka, but rather as a backup player to ease Saka's burden and fill in for him when he's injured.
I don’t think anyone will even think Madueke will replace saka, what is Madueke playing that will make him replace saka, which player will Arsenal even be signing that will replace saka for now? I don’t think there is any player, Madueke is just a backup player, and am sure they won’t be using saka frequently again, matches which they known that it won’t really be difficult for them, am sure they will bench saka and use Madueke, or maybe when Arsenal are already winning confidently, then they will bring Madueke into the match.
Madueke coming to Arsenal will never affect any Arsenal players or Arsenal attackers, Madueke will always be a back up player whenever saka have injury or any attackers had injury, Madueke can not play as a left winger because that is another reason why he decided to leave Chelsea and join Arsenal, Arsenal sign Madueke to be a back up for Saka rest Saka in some games because it has been more than 3 seasons Arsenal did not have any back up player that can assist Saka when he got injured.
There will be a lot of challenges next season for Arsenal because the new signings Arsenal will have many attackers, Arsenal will have 3 strikers, Jesus, Kai Havertz and Gyokeres and those players are all good players but with I think one of them will leave after next season and it will be Gabriel Jesus because he has not been good enough to help the team since they signed him, injury has made Arsenal lost their confidence in Jesus.