Maybe you are, though your posts suggests otherwise.
The first goal isn't all that difficult to break down. As soon as the ball is played in behind to Reguilon, De Gea looks up to see if there are players making runs that he has to be aware of and sees the Sevilla player down the middle, he then has to position himself close to the post in case Reguilon goes for a shot instead of crossing it. Reguilon crosses it low, De Gea has to stop briefly and look up to see if the Sevilla player in the middle gets on it or not, then has to rush over and attempt to position himself for a shot from 6 yards out..Suso hits it will and there's plenty of power on it.
Obviously he can gamble and dive before Suso hits it, but would look like a proper twat if the ball rolled down the middle and he jumps away from it...
So no, there's nothing wrong with the goalkeeping for Sevillas first goal.