Qwiss Nwaneri started the season in the 22 as Odegaard's understudy, so we haven't really gained there. We could replace Sterling with more of an AM type if we wanted Ethan as more a winger, but we still need to replace him. Although as I said in another thread, I'm starting to think they'll sell Martinelli and we'll end up with Saka, Williams (or similar), Odegaard as our main trio behind the striker, with Trossard and Nwaneri as the primary cover, and then the final spot will be left to Jesus and Dowman to compete for.
Qwiss I'm not sure you even get a good 4th choice CB. And I am sure if we had one they'd be rusty as fuck whenever we needed them because Arteta would never give them minutes. How many minutes did Kiwior get before Gabriel went down? And he was 3rd choice.
I think you need to aim for someone who is on the younger side who won't mind limited minutes, and who is versatile and can plug gaps elsewhere in the team as needed. Not easy, but can be costly not to have that 8th defender.