I will reiterate what i posted even when he scored twice against Villa, currently he is not good enough for a team who wants to achieve top 4 finish, specially playing as part of the front three.
He is still very raw and needs to develop several important aspects of his game which includes finishing, crossing, general passing and physicality. Plus he has this head down approach on the break, where he never has his head up or tries to find anybody either he tries stupid shots from awkward angles or he ends up losing the ball getting crowded and subsequent fouling in frustration.
You compare his approach play with Amad today, Amad was levels above, his constant pass and move and always in control of the ball, trying to pick people out, which Garnacho is never able to do with ease.
His best use was last season when he was brought on against tired legs to stretch the play. But due to Antony being himself and Sancho not available, he has been played non-stop which should never be the case.