Summary
Bullock is one of those classic 3-and-D wings that isn't great at either of those aspects. However, being solid at both is good enough to stick around in the league, and that's exactly what Bullock has done. Bullock has shown somewhat recently he can be a starter on a solid team, as the '20-'21 Knicks were one of the most surprising teams of that season, and he later started all 18 playoff games for the Mavs in their 2022 Western Conference Finals run. 

Over the last four seasons, Bullock has shot over 39% from three on nearly six attempts per game. He doesn't provide much else offensively, as over 77% of his total attempts have come from 3-point range during that time. He isn't a playmaker for others off the dribble, and he doesn't create for himself either as over 93% of his total attempts have been assisted, and over 98% of his 3-point attempts, according to Cleaning the Glass.

Defensively, Bullock has good size for a wing, and can guard multiple positions. He may not be the one you want guarding the elite wings, but he can hold his own in most matchups. With the Mavericks, Dorian Finney-Smith usually guarded the #1 option and Bullock guarded the #2 option. Bullock also isn't a very disruptive defender, with below-average steal and block rates. 

Bullock will be 33 years old as a free agent in 2024, so teams might be wary of some slight decline in upcoming seasons. He didn't get many minutes for the Rockets in '23-'24, which could hurt him heading into free agency, and there's a chance he could fall out of the league soon.
 
Cap Considerations
Bullock will be an unrestricted free agent with a $2.1 million cap hold and Non-Bird Rights. This means that the highest starting salary the Rockets could offer him using the Non-Bird Exception is $4 million. This should be enough to retain Bullock, since he settled for the minimum to come to Houston. Alternatively, the Rockets could use cap space or their their Mid-Level Exception or Bi-Annual Exception to re-sign Bullock if he demands more than $4 million. 

Other teams will have multiple ways to sign Bullock as even teams without cap space could use the Non-Taxpayer MLE, Room MLE, or possibly even the Taxpayer MLE, or Bi-Annual Exception to sign him. It's also possible that Bullock only gets minimum offers, and he may not even get fully-guaranteed offers.