In Texas, any center fire ammo is legal.
Switching to coyotes is one way to stay challenged. Different firearms/ archery is another.
The reason you get stuck on routine hunts is because you learn what works and what doesn't and you develope a routine... Especially with game animals, because you want that trophy and meat in the cooler.
Switching to varmints can result in free hunting opportunities and the challenges and rewards can come with it. Can still get trophies that way also.