Just for everyone's information, the db strength is stronger with a lower number. -60 is horrible signal strength. When I do Wireless site surveys, if we hit -60 to -80 we consider that unusable. That being said, my app works when the traeger is showing -68db. The issue is on the backside in tragers hosted application that the grill talks to and feeds the app. It does not feed directly to the app, it goes through servers in the cloud.
This is similar to your phone talking to Onstar before sending the signal to my truck to start. Same concept as there is a server in the cloud in between adding an additional variable. Connecting to the "Internet" is not the problem many times.
Traeger needed to put an external antenna on that controller like the higher end models. Putting that controller in a metal box helps nobody.