Assuming the wires are all good, are there any loose connections? Have you run a continuity check on the power cord? With the controller off, is the element getting hot?
If you suspect the heating element, test it as well. Another test you can try is plugging in an iron and see if the breaker trips when it is heating up; if it trips, you have a faulty breaker OR a breaker not rated for the appliance, expressed in amps. Breakers, and GFCI type outlets will go bad over time. Also, when you say breaker, is this the breaker in the service panel? Or are you referring to a GFCI outlet(s).
Rare but it is possible that the smoker is pulling more amps than the breaker is rated for. To check, you will need a clamp amp meter and to avoid cutting the power cord sheathing, a line splitter (see link 3 for images). The first 2 links are of possible help in your situation; the last link is test equipment oriented and I am not suggesting you buy. But such a set up will do volts ac/dc, continuity, and current as well as testing outlets and gfci outlets, eliminating the need for a separate multimeter and amp meter. Again, I am not suggesting you buy this unless you see a use for it around the house and you like to tinker with electrical items.
Lastly, and maybe I should have mentioned it first is the warranty. Is your smoker still under warranty?
https://housetechlab.com/how-to-find-a-ground-fault-with-a-multimeter/
http://www.appliance411.com/faq/test-element.shtml
https://www.amazon.com/Amprobe-4560562-AMP-320-Clamp-Meter/dp/B0185F83Z0/ref=sr_1_1?dchild=1&keywords=amprobe%2B320%2Bmultimeter&qid=1603581017&sr=8-1&th=1