Neither team should rush into a decision given that there are 4 weeks left, but at some point they need to leave themselves enough time to find replacements.
We also need to ask ourselves how much Aouar is worth to us. If it gets late in the game, for example, would we be willing to give up someone like Nelson? Where does he feature in our rotation in the next 2 years? If we are playing 433 and we have Pépé/ Willian for the 2 right wing spots. And then for the 8/10 spots have Ceballos/Aouar/ Willian/ESR, and Aubameyang/Saka on the left, and Lacazette/Nketiah/Martinelli in the middle. It might actually be worth giving him up for a starter.