Yea, I may have overstated it, but I can't see Butler being a top 10 player, mostly because of how much time he spends not playing basketball with all his inuries.
I think he slots in with a bunch of guys in the 10-20 range after Lebron, Curry, Durant, Harden, Davis, Paul, Kawhi, Giannis, Westbrook, Embiid, and probably a few others
Is he a clear, no doubt, top 20 player? Even ignoring contract and future production, who would each team refuse to trade for Butler straight up?
These teams probably have no players that are currently equal or better than Butler - Clippers, Suns, Kings, Hawks, Heat, Magic, Mavs, Memphis, Spurs, Nets,Bulls, Cavs, Pistons , Knicks (though Kristaps if he wasn't hurt)
These players might be traded straight up(one year, no consideration of fit, contract or future):
Boston - Tatum,
TO - Lowry
Nuggets - Murray
Jazz - Mitchell
Wizards - Wall
These players would likely not be traded straight up for Butler:
Boston - Kyrie,Horford
76ers - Embiid,Simmons
Raptors - Kawhi
Pacers - Oladipo
Bucks - Giannis
Nuggets - Jokic
Minn - KAT
OKC - Westbrook, George
Portland - Lillard
Jazz - Gobert
Warriors - Curry, Durant, Klay, Draymond
Lakers - LeBron
Hornets - Kemba
Rockets - Paul, Harden
Pelicans - Jrue, Davis
Of course, that is a subjective list, but even if you remove Kyrie or Kemba or Jrue, that would still be 20 players.