1. Leave it in a bit longer. Brisket gets moist/soft when it sits at higher temperatures longer. If it's tough, there is a good chance that you just need to leave it in longer (I'll leave it up to 205 degrees). I also use 2 thermometers, one in the flat and one in the point and position the brisket to try to get them both to at least 203 together. The Traeger brined brisket recipe is pretty straightforward: https://www.traeger.com/uk/en/recipes/brined-brisket?srsltid=AfmBOoruRH9TOeijuuc19XpQ_XID7nLU7GoP6A5ptSQ0sZaZFEbPXN5u

2. As a failsafe, try brining the brisket overnight then dry rubbing it lightly right before smoking it (or even dry brining it by rubbing it the night before and leaving it in the fridge). Brining will soften the brisket. I will sometimes do this if I can't find a Prime brisket (which my Costco hasn't had for the past 9 months or so).

And of course, let it sit. Wrapping it in a towel and placing it in a cooler for an hour or two before eating it can have a big impact on the end quality.

Most of all, don't give up! Brisket can take a lot of effort to master (I've done over 100 and I still have an occasional brisket I'm disappointed in).