Arsenal has two strikers available, Havertz and Gabriel. They don't mind adding a new striker. They think those two names are enough to help them this season. They are focusing on other positions, not the striker position. They scored a lot last season. It's probably their reason to feel confident enough with their available strikers. And they decided not to sign a new striker.
I also think that it's not a problem for Arsenal when they don't recruit a new striker, although it wouldn't be wrong if Arsenal wanted to recruit another new striker to replace one of them if they get injured during the season. However, the reason you said could also be very logical because Arsenal also thinks more about other more important lines such as the midfield and defense so that the opposing team will not easily break into their goal when competing in any competition.
Arsenal have a good attack, but they are having problems in defense this season. For example,
in the Premier League,
they made 5 games and
conceded 7 goals. That is not good. Because usually the teams that become champions are because they had a good attack but also an excellent defense. In the European Champions League, Arsenal's attack was inefficient. When they played against Atalanta, they failed to score a goal. Note that Atalanta is not doing well in Serie A. They were an opponent that Arsenal could have beaten. Arsenal's next game:
Arsenal - PSGThis will be a very difficult game for Arsenal. The chances of them losing are high. So, in my opinion, Arsenal will not do well in the European Champions League. It seems to me that they have not managed to be the type of team that aims to win European competitions.