Step 1: go to the server settings before loading the game, and set Dino Damage to zero
Step 2: start the game
Step 3: find the Rex
Step 4: punch it so many times until he passes out... he may run away so get him stuck in a wall or something
Quick Notice step 4: it may die if you punch it to many times
Step 5: tame it
Step 6: enjoy having your OP Rex or not
This is how i got a Rex :) :) :)
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!
Even early game they're not too hard to tame. Get yourself an Iguanodon and put it on all fours, then it will never run out of stamina. Run back and forth shooting the Rex it will never catch you. Just got one with tranq arrows and a bow, but you could do the same with stone arrows if you wanted to kill it.
If you're using a taming pen for rexes, build it at least three walls high. Sure you are able to keep it inside the two walls high pen, but an especially cheeky rex might climb out of it, which is definitely not going to end well for you.
Place 1 stone foundation near the rex you want to tame, (not too close) then 1 doorframe and door, both stone. Then place 3 stone walls around it. Add an extra layer on top of the base structure of stone doorframes then cap it of with a ceiling. Shoot the rex to get it’s attention, then run inside and the rex won’t be able to hit you, but you’ll be able to shoot it. This trap also works for Spinosaurus and dire bears.
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.