For my more open-area coyote hunting, my general strategy is to turn off the call when the coyote gets around 150 yards, and then I stop the coyote somewhere between around 125-100 yards. Usually a simple whistle, hey, mouth bark, etc will work. This is if they are coming nice and steady. Odd things start to happen if you let coyotes get too close. If I can't kill a coyote consistently at that distance standing still, I need to quit hunting coyotes. If they are coming absolutely on fire, I will stop the call around 200 and sometimes you have to get really loud and sometimes aggressive to get them to stop.
The only time I am shooting at coyotes past 200 yards is if they are about to get my wind or it is the 2nd, 3rd etc coyote and the others are already dead.
I am comfortable to 300 but have shot many coyotes over 400 but again these longer shots are almost on multiples where I shot one or more, and I wait for the coyote to stop. This range is going to depend on your gun, quality of thermal image, magnification of image, etc.