Brake controller

As far as your vehicle goes, your owners manual will tell you if trailer brakes are required. Generally most vehicles state that brakes are required over a certain weight, often that weight is as little as 1000 pounds. Obviously both Tab models exceed that even empty.

From an insurance/liability standpoint, if trailer brakes are provided on the trailer, it’s expected you will utilize them. Not doing so could potentially put you at risk of greater liability in an accident. 

On a practical level, the Tacoma could probably manage a 320 without brakes. But common sense wise, it makes sense to protect your expensive trailer by adding a new brake controller. Yes, it stinks that you have a $300 paperweight, but spending another $300 is better than endangering your RV or other people on the road. If you want to stay wireless, the Tekonsha Prodigy RF is a popular choice that isn’t dependent on your phone.

From what I understand if you have set up the controller in the past it continues to work even without the phone connection. Obviously you won't be able to change the settings or use the manual override. 
Depending on your proclivity for digging into things here's what I would do: As it is a bluetooth device there should be a FCC ID on it somewhere. Use that to figure out who actually makes the thing. (Curt is more into welding than assembling SMD PCBs  ) Slim chance the FCC docs might reveal how the pin is calculated but there may be some contact info.