Arsenal's defensive side is already quite good and could be quite good if it can still survive next season. However, Arsenal still needs to improve the attacking side before the new season starts because after all the attacking players must have better finishing instincts so that the team can get more goals in each match. In general, Arsenal is no longer bad if you look at their achievements last season, although Arsenal still need to make some more improvements in order to continue competing for the title next season.
Arsenal has experienced an improvement in their performance and also their game so far, in the last few seasons Arsenal has been able to surprise us by competing as a challenger for the English league title, but even so we cannot deny that the performance and mentality possessed by Arsenal is not enough for them to compete in the Champions League, currently Arsenal has a squad that is quite capable with a combination of young and senior players, So indeed Arteta is able to combine the performance, speed and stamina of young players with the experience and also mentality possessed by senior players so far.
The Arsenal squad does look quite balanced this season, they have a formidable defense with a gabriel and saliba and also support with strong midfield support from Declan Rice, while their attacking line is actually still quite good and we can see how they are able to beat other teams in the league with big scores in match, but indeed what you say is true, Because currently the depth of the Arsenal squad, especially the attacking line, is still not qualified, the absence of a central striker and also a decent substitute when the main player is injured is of course a homework that must be improved by Arteta at this time, so far I admit if they deserve to be title contenders in the Premier League but for the Champions League of course they are still not strong enough to compete.