Trading Davis Mills
The crux of this argument would be how much value you can get for Davis Mills. The Texans most likely aren't getting anything better than a sixth-round pick for Davis Mills. Even still, that feels high. One of the worst teams in football last year, the Texans struggled mightily to find success behind a Davis Mills-led offense.
Texans would need Mills to play immaculately during the preseason to get actual value back for the third-year quarterback. While teams typically overvalue young quarterbacks with positive traits and experience, Mills needs to recoup lost value from his previous season. They would trade him if the Texans got offered a day-two pick for Mills. That hasn't happened and probably won't ever happen. That's why he's still on the roster.
Ultimately, the final verdict for me would be keeping Davis Mills makes the most sense.
With a coaching staff with a history of keeping three quarterbacks on the roster and Mills' affordable contract, he makes a ton of sense to come into the year fighting for the number two spot behind CJ Stroud.