There are four major flaws in your argument for Giannis.
#1: Massive amount of help. You turn the same argument on its head in support of Giannis. Giannis is surrounded by teammates who boast the highest defensive ratings in the NBA.
In the Lakers’ system, Davis has far more responsibilities than Giannis, as he is called on to guard the best wing, or switch onto guards. You can only be the free safety when you’re guarding a less dangerous opposing player.
#2: Overcoming mistakes. There are six words which prove, beyond a shadow of a doubt that Davis should be the DPOY:
Rajon Rondo, Kentavious Caldwell-Pope, Kyle Kuzma
Any player who can carry bench lineups that feature the corpse of Rondo and two erratic defenders who get lost on rotations is playing unbelievable defense.
Davis has to go out and contest 3-point shooters because his teammates on the wing screw up so many assignments.
#3: Team defensive ratings. If we look at 5-man lineups that have played at least 15 games, we get a very different picture at what Davis has done compared to Giannis:
Here are the defensive ratings when Anthony Davis plays with:
LeBron, Green, KCP, Caruso: 88.0
James, Green, KCP, Kuzma: 89.2
James, KCP, Caruso, Kuzma: 89.7
James, Green, Bradley, Kuzma: 90.9
James, KCP, Kuzma, Rondo: 93.2
Here are the defensive ratings when Giannis plays with:
Lopez, Matthews, Bledsoe, Middleton: 89.8
Lopez, Middleton, Bledsoe, DiVincenzo: 93.4
Lopez, Matthews, Bledsoe, DiVincenzo: 98.4
#4: Other handicaps. The problem for the Lakers is dealing with so much political bullshit, as Rondo and Bradley have to play big minutes, instead of playing the best three guards in Green, Caruso, and KCP. Coach Vogel has to walk on eggshells to keep LeBron and Davis happy (i.e. playing with their buddy Rondo) while at the same time try to win games. Vogel is looking over his shoulder at Jason Kidd, who was brought in as an assistant but wants to be the head coach of the Lakers.
Davis is the key reason the Lakers remain a top 3 defense in spite of the horrible regular season lineups and substitution patterns. Seeing Rondo playing in crunch time or getting more minutes than Caruso makes every Lakers fan scream at the TV.
On the other hand, Giannis is young, and hasn’t won anything yet. He has nowhere near the same size ego and desire to control everything as LeBron. The Bucks have bought in completely into their coach’s system, and each player’s role is established.
Final DPOY rankings
5. Leonard is up the at the top, but missed too many games.
4. Gobert was unplayable at times against small ball lineups. If your best defensive player can be benched in certain situations, because he can’t defend on the wing, there’s no way he can be the DPOY.
3. Lopez has been great protecting the rim, but he doesn’t have any other responsibility. And he gets a huge boost from Budenholzer’s system. If you watch game film, you will Milwaukee guards will cheat off 3-point shooters to protect the rim. That’s why the Bucks are the worst team in the league in giving up 3-point shots, and why they’ve lost games this season against teams that get hot from beyond the arc. They lost to Toronto because Vanvleet got hot and the Bucks made no adjustments in their defensive scheme.
2. Giannis has been incredible this season and dominated so many statistical categories, but he is in perfect system built around him and surrounded by excellent defenders on the perimeter.
DPOY Anthony Davis — this season he has shown the versatility and range of Kevin Garnett. I’ve seen him contest a 3-point shooter then recover to block a shot at the rim. I’ve seen him jump out to contest an open 3-point shooter when a teammate missed a rotation. I saw him fly by an opponent while contesting a 3-point shot, then recover and block the shot. He can defeat pick and rolls almost by himself as he can contest the guard and still recover to block the guy rolling to the basket. He picks up guards on the perimeter and blocks shots or steals the ball. He plays help defense
These highlights include him taking on James Harden and just swallowing up that annoying step back/travel, bodying up and blocking Jokic, stripping the ball against players in the paint, and intercepting passes by penetrating guards trying to find open 3-point shooters.