for me it's all down to Rashford's influence on Ederson, not Akanji. Ederson clearly has to keep Rashford in mind, he cant see across the line from back in goal, Ederson doesn't have the same feeling for whether it's well offside or a VAR lines on the telly job, so he must assume Rashford is in play as he is steaming towards goal. Therefore Ederson is influenced, Rashford has clearly intefered. The little back lift of Rashford's left foot is just another reason to disallow. I cant believe this blatant offside is even being discussed in technicalities but it's where the game rules have gone now.