Let me tell you how I got my Rexes I just got 10-15 Giant Bear Traps and placed it all down and and started using my tranq arrows and running to the bear traps like a PUS- and he would get stuck and still would want to chase me you poor bas- then he would try to run but I would chase him and knock him down.
If you use the bear trap strategy which is if you lead it into a Dino gateway that is shaped in a triangle and with a bear trap in the middle (Large Beartrap) and when it is stuck you must put a dinogate behind it to trap it and then knock out.
The Rex are very slow . Put a stone gates around him while he is stuck and use a bear trap then put the x3-x4 stone gates then tranq him out . Make sure you clear the area before setting the bear traps others creature can spring it and u would be left with using your self or a tanky dino for a distraction
I would think these were gonna be harder to tame but they’re actually not that hard, my stamina and movement speed is pretty high I’d say around 200 or higher but I didn’t need a trap or any of that, all I used was tranq arrows, u shoot it once then run away for a little bit turn around quick shoot it again then run away again and shoot it again and repeat, if it starts running it means it’s almost knocked out just chase after it and keep shooting and feed it meat!