Offense not designed for him
The Cincinnati Bengals offense was largely designed around Mixon for a lot of years. Marvin Lewis loved having the power back, and with Andy Dalton starting to show his age in 2017, Mixon was a nice asset. Mixon was the most reliable piece of their offense from 2017 to 2019. Then they drafted Joe Mixon and needed to rely on him just a bit more over the next two seasons.
By 2022, however, Burrow was one of the stars of the league and Mixon's involvement in the offense declined significantly. Especially as they added more and more receivers. Mixon still had the fourth most receiving yards on the team in 2022, but it was clear that the Bengals were no longer in need of his services.
With the Houston Texans having Stefon Diggs, Nico Collins, Tank Dell, Noah Brown, and Dalton Schultz to throw to, the addition of Mixon won't impact the game. At least not the passing game. He's likely the sixth-best receiver on the team, and that's being generous. C.J. Stroud is likely to throw far more in 2024 than he did in 2023. Upping his rookie total from 499 to probably closer to 600 attempts for the season.
With Mixon needing 250 carries just to hit 1,000 yards, and the likelihood he's splitting carries with Dameon Pierce in 2024, Mixon won't impact the game like many hope. He's not known for his top-end speed, or his ability to outrun time defenders. He's a guy who, much like Derrick Henry, needs time to wear a defense down. Reps that Mixon won't get in Houston.