Jesus.
I think you're being incredibly harsh on him before last season. He got 5 league assists in 17/18 and was pushing out Walker (alright there were disputes which contributed to that, but his performances were good) as well as getting 3 assists in the Champions League. The defensive issues were always there but when the system was right and he had cover, he was a reliable threat from wing back, earning his England call up and eventually becoming first choice for his country as well as his club. Are you sure you're not just a teensy bit blinded by your dislike for him?
I agree in 18/19 he fell apart, and on the back of that I wasn't too arsed when he was sold. But the way he's improved and shone at Atletico does make me wonder whether his shite form in 18/19 was purely down to him, or a larger indication that some players in our team are just not playing to their level, especially some of our defensive players. Either way, even if is crap, I know we can agree that if you sell a player because he's not good enough, you at least have to bring forward another option who is good enough .. which we didn't do, at all.