Playing without Odegaard and Bukayo Saka has clearly affected Arsenal's performance but I think it only has an impact on their creativity, while their defensive line should be fine. What made Arsenal lose was that they had to play with 10 men from the early minutes, and the red card was enough to affect their composure, so when Bournemouth succeeded in breaking down the deadlock, this actually made Arsenal even more shaky, so that instead of equalizing, they conceded the second goal.
Arsenal only thought about adding more defensive players during the transfer window, forgetting that they didn't have any top players to replace Saka and Odegaard if they couldn't play. Other teams are busy acquiring more players to improve their performance each time their current players aren't fit. I stated during the transfer window that Arsenals performance would no doubt suffer if they didn't acquire another left winger this season because they shouldn't expect Saka to be fit all the time. The players didn't have much time to recover after the international matches, so they continued playing in the league, and it's clear that Saka won't be fit with how many games he has played so far.
However, Arteta did not have a left winger who could replace Saka's position in the Champions League match against Shakhtar Donetsk, so he used their striker, Gabriel Jesus, to fill the role. To be honest, Arsenal failed to learn from their previous errors. Manchester City, who had won the league title four times in a row, strengthened their performance by adding more attacking players, but Arsenal, who had failed the previous two seasons, relied on their current players this season.
