I think the only reason Arsenal sign Eze is to backup in case Saka is tired or injured, because he's playing in left wing position. He's mainly an attacking midfielder, but Arteta is a coach who lack of strategy, they always play with classic 4-3-3 formation.
If Eze played as a midfield in this classic formation, I don't think he will perform.
The big change should be happen from Gyokeres, he should score many goals.
Eze is coming as a starter not a backup. Saka plays RW, Eze plays LW which has been their weakest link for some time now, they've been struggling to fill that position. He's going to own that LW.
This is arguably the best internal transfer of the summer after Kudus to Totteham for me. Can't believe Totteham bottled this transfer, they could've wrapped it up some weeks ago but kept on twerking back and forth.