Arsenal is a very good team and I agree with you that they will be able to have an excellent run in the champion league considering the fact that they have made some excellent signings and above all Jorginho has signed the renewal of his contract with Arsenal which personally is a a player who I like very much even if he didn't shine in these European games with Italy but he will have time to make up for it on the big stages
I also see Arsenal as a team that can still be quite strong next season so that some of their closest rivals last season also still have to be wary of Arsenal as their competitor in the race for the Premier League trophy. Likewise in the Champions League because Arsenal could perform better next season and be able to reach a quite crucial stage so that their rivals will still see Arsenal as an opponent that needs to be eliminated early before heading to the quite crucial stages in the Champions League.
Last season we saw Arsenal could compete closely with Manchester City even though they finally had to end the season as runners-up, currently Arsenal has not been seen to have made many improvements to their team even though it is linked with many star players who will be recruited, but different with the rival Arsenal team in the league has improved their squad so we will see a fierce competition will happen next season and if Arsenal does not improve their team now then next season is difficult seeing them compete in the Premier League, especially the Champions League which is filled with the best teams in Europe at the moment, last season Arsenal was only able to penetrate the quarterfinals and it was an impressive achievement compared to the previous seasons Arsenal in the Champions League, but seeing the current Arsenal situation actually makes me doubt that they will be better next season in the Champions League, Moreover, next season every team that plays in the Champions League will get more matches to play than last season and for that they need a very capable squad to face it.