I agree with you and I also see that the weakness lies in the mentality. Almost all of Arsenal's players have great abilities, but they lack the mentality that has led to their failure to win the Premier League title in the previous three seasons.
Arteta needs to improve the players' mentality when facing competition, as they have so far lacked confidence.
Finishing second in the standings for three seasons isn't bad considering the quality of the players Arsenal have, so they need to develop a winning mentality for next season.
Arsenal has always come close to winning the Premier League title. In recent seasons, Arsenal has come even closer to winning the title. However, the team has often been unlucky, with key players suffering injuries that have caused their performance to decline, resulting in many draws. The following season saw a similar situation unfold. The main issue, however, is the players' mentality, which sometimes seems to lack confidence during matches, leading to lost points. In terms of consistency, Arsenal can be said to be fairly consistent. But personally, I sometimes wonder what's missing from this team. However, it's clear that Arsenal has failed due to injuries and having a weak bench. But those issues have been addressed. And in recent seasons, the problem might have been the players' confidence, which doesn't always seem consistent.
But this season, Arsenal must prove that they can achieve success. Because if they don't, Arsenal will be heavily criticized. And I will feel quite sorry for Arteta.