Yes, it's tough to evaluate players like Paredes because they require competent teammates to show their ability.
You can take Kessie, and put him on any field. His performance is not affected by teammates. His main qualities are running, work rate, tackling and strength. So you can exhibit these qualities even on a terrible team, maybe even moreso on a terrible team.
Now you take Paredes who is playing at Empoli. When he aims a pass, he is aiming at fucking Massimo Maccarone. Because Maccarone can't even run, the pass radius has to be even smaller for Paredes. For example, Kroos can smash a ball anywhere near Bale and people will call it a perfect pass but really Bale just gets to every ball.
So it's hard to evaluate what the true talent of the players is in difficult circumstances. That's why when I see the technique Paredes has, in terms of actual fundamentals of striking a ball, how he sees openings before he gets the ball, his balance on the ball and things like that, I have to believe in him.
This is just my opinion of course. I could be wrong. Maybe in a team like ours it turns out that he will miss 4 out of 10 key passes. Maybe he gets lazy. Maybe he doesn't know how to read the game defensively or whatever.