One could conclude from these basic numbers that Mills is roughly in the middle of the pack, an average rookie quarterback compared to the others in his class. I think that pairs pretty well with the eye test - he hasn't been as polished as Mac Jones or as flashy as Trevor Lawrence, but he also hasn't had as many ugly performances as Zach Wilson and Justin Fields.
There will be arguments made that Mills - with only 11 collegiate starts and having a third round draft pedigree - should be praised for playing statistically better than some first round quarterbacks with far more starting experience and I would agree with that… to an extent.
If you've followed me for long enough you'll know that I don't put all my stock into box score stats as they are often deceiving. Adding context in the form of film, advanced stats and team construction/scheme helps us accurately evaluate players, especially the quarterback position which is impacted by numerous factors.
With that being said, Davis Mills has had similarly poor and in my opinion, better team surroundings than the two quarterbacks he's arguably played better than - Wilson and Fields - which helps inflate his stats when comparing the three.
The biggest pro-Mills argument is that he's held back by play calling and I agree, but so have Fields and Wilson. It's clear that Tim Kelly runs the ball too much during neutral game scripts especially when the Texans are last in the NFL in rush offense DVOA (per Football Outsiders) plus Kelly has a fetish for WR screens that we fail to block well. Both of these factors do hurt Mills' chance at success as he's faced plenty of disadvantageous 3rd and long situations.
Similarly, Bears play caller Matt Nagy is a quarterback destroyer - not whisperer - who has set up Fields to fail by running an absurd amount of 5-wide formations (OL has no blocking help via RBs or TEs) which is mad-scientist-level-crazy when the Bears have the worst pass protecting offensive line in the NFL (per Football Outsiders). Nagy also fails to get Fields in rhythm with easy looks off of play action or bootlegs and is such a poor communicator that they told Fields he had a free play when he didn't, leading to an interception.
Furthermore, Jets offensive coordinator Mike LaFleur is a rookie at leading an offense himself and has failed to scheme around Zach Wilson's strengths that he displayed at BYU - being allergic to play action, bootlegs and struggling to time and space those concepts properly when they do finally call them. LaFleur has simultaneously put too much on Wilson's plate, asking him to operate drop back passing concepts that require a veteran level of mental execution but also handicapping Wilson by calling plenty of throws behind the line of scrimmage (25 compared to Mills' 32) leading to poor yards/attempt (Wilson and Mills both average 6.5).
Apart from play calling, these three quarterbacks also do not have much talent around them, but I would argue that Mills has the best of the three offenses which helps boost his numbers. Starting with the offensive line and for as bad as the Texans has been at run blocking, they rank 19th in Football Outsiders "Pass Protection" metric whereas the Bears rank dead last in the NFL at 32nd and the Jets rank 30th.
Furthermore, Mills has the best wide receiver on the Texans, Bears or Jets - Brandin Cooks is on pace for another 1,000+ yard season and has an absurd catch rate of 73% (career high since rookie season). With how much rookie quarterbacks tend to lean on their WR1, Mills has a distinct advantage over both Fields (Allen Robinson has the least separation yards of his career) and Wilson (Corey Davis has missed two games and only has 50+ yards in two games). Their supporting casts are pretty comparable, with Mills having Nico Collins+Danny Amendola, Fields having Darnell Mooney+Marquise Goodwin and Wilson having Elijah Moore+Keelan Cole.
I bring these points up not to entirely discredit Mills' performance (he's been fairly average for a rookie) but to provide context which should cool down the talks that he is a better player than Fields and Wilson. Will he be one day? I can't rule that out, but if I asked you if you'd rather have Fields, Wilson or Mills as the Texans quarterback of the future, I think the answer to that question would display where the confidence in the room is leaning and leads to my next point.