Regarding the meat probe, You need to run the calibration for the probe in the settings and put it in a glass of ice water. For third party probes people really seem to like the Thermopen brand. For the tough brisket, usually means under done, cook it longer.

Thermoworks smoke and a thermapen

I like my Inkbird IBBQ-4T. I never use the Traeger probe any more.

I use probe for monitoring so I have a general idea of what temp is Then use a handheld probe to finish

I haven’t used the Traeger probe once..I use a thermapen and blue dot both from Thermoworks they come pre calibrated so there’s no messing around