I see that Arsenal is solving this problem, now it seems that Arsenal is making several transfers that allow for an equal quality between the main and reserve players so that if there is a player rotation it will not have a significant effect on the team's performance.
I think it's very likely that Arsenal will do well in the Champions League next season, the quality of this team is increasing now and they deserve to be reckoned with.
Arsenal really shouldn't be underestimated next season, especially in the Champions League because Arsenal themselves are also very aware that they still have to improve on existing deficiencies to be able to wade through an even greater next season. And not only in the Champions League, Arsenal must be taken into account, but also in the Premier League must also be considered from the start of the season, because Arsenal will try to be consistent from the start of the season to fight for the title next season.
Arsenal are one of the most active Premier League teams in the transfer market, Arteta is very aware of the shortcomings that the team he leads still has. Arteta tries to bring in quality players in order to keep the team's performance consistent in every game. Arsenal will try to give their best performance in the Champions League even though they are currently not placed in the favorite team.
Arteta will try to make a surprise in the UCL this season, their performance last season was very good even though in several matches they had lost important points in the Premier League. The arrival of new players is expected to add to Arsenal's strength as well as close the gap that has not been resolved last season. Arteta will try to take advantage of this season after they failed last season, the UCL is of course their main target.