Out of the current squad I think Lloris, Romero, Bentancur, Skipp, Kulusevski, Son and Kane are of a quality I would class as 'top 4'.
Reguilon, Dier, Hojbjerg, Winks, Lucas, Tanganga and Bergwijn are of a top 10 quality, most of the time, with capabilities of performing at a top 4 level - but rarely show it. Out of all of them, I think Bergwijn could benefit the most under Conte.
Sanchez, Davies and Doherty are simply not able to reach top 4 level any more. They may have the odd game where they play a blinder but they are mid-table quality.
I refuse to make judgement on Royal, Rodon, Gollini or Sessegnon yet. I think Royal is young and its only his first season in the PL. I've seen plenty of players arrive and look like total arse but suddenly look loads better in their second season. Gollini has hardly played and I don't like to judge players unless they have a run of games. Rodon hasnt been given a chance and he must be terrible in training if he cannot get in ahead of Sanchez or Davies at the moment. Sessegnon is still young, has had horrible injury issues and needs regular game time. There is definitely a player there, but the club are failing him at the moment.