I'm not sure "former Juventus midfielder" is necessarily a sign of quality if someone plays a handful of games for them. Adama Traore is a former Barcelona player but few Villa fans are pining for his return. I don't think central midfield is the area we are struggling with this season, and it will be even less of a priority when Onana and Tielemans are back.
My main issue with loaning him to Benfica is that I'm not sure they have the ability to give us a shit-tonne of cash to enable us to re-invest in areas of greater need, such as literally all the attacking positions.