Arsenal again playing very poorly at the end of the season, as in previous seasons, but last season Manchester City overtook Arsenal in the table and became champion. This time Newcastle could beat Arcanal, cause Newcastle are only 2 points behind Arsenal.
Of the last 5 games, Arsenal lost 3 and drew twice and this is when Saka returned from injury, so most likely Arsenal have psychological problems, when the team can not adjust to the end of the season and starts to lose or draw at the most inopportune moment.
Arsenal declining is not a surprising one; they continue doing this every ending of the season, although even though they focus more on the Champions League competition, I think they should do better since they get eliminated from the Champions League, but Arsenal did not still recover; they keep recording poor performances in the Champions League again.
Instead, they should focus on how to finish the season in a good position in the table; Arsenal are about to leave the second position to Newcastle United again. With the way Arsenal's performance is going right now, Newcastle could win their next match against them.
Arteta is not to be blamed for the misfortunes of the team although it’s true that he made some mistakes in his decision-making at different intervals but the players also were not efficient enough this season. They couldn’t maintain the consistency level until the end of the season which cost them the league trophy as well as the Champions League.
Arteta should be blamed because he's the one managing the squad; whatever the problem is, he should be the one to solve and for him to be unable to solve the problem, he should be blamed. The same mistakes have been happening for seasons now, and you said the manager should not be blamed. However, if you are talking of players, Arteta is still the one to be blamed because any position that needed to be fixed, he would do that before the season got started to avoid the same issue.