What's your cooking temperature? Like JD said above, you need to keep the temps as low as possible to get visible smoke, usually 170-195 for an hour then turn up as desired. Sometimes it's a struggle to keep it low especially if it's hot outside. I have even propped the door open a little bit...
I wanted a constant 165* last weekend for smoking some ribeyes and the lowest it would go is 200*. If I cracked the door open just a little bit it would go down and produce more smoke. Next time I'll play with the stack cap elevation to see it that helps.
I've been doing fine with the 575 so far. For searing I use my charcoal grill. The Traeger now goes to 500* with the new firmware but the charcoal sear adds a flavor of it's own and sears instantly. I still haven't bought the folding front shelf. Just stubborn I guess.
If you want a deal go to Costco and look at the Silverton. Comes with shelves, cover, pellets and lower cabinet for less than the bare grill. I think they have the 620 and 810 sizes, $799 and $1,350 on line and less in the store. The 810 has super smoke but I don't miss it with my 570, I just...
If you have melted plastic on the thermocouple, just scrape it off under heat. I seriously doubt it would be damaged. Are you using the meat probe? Did you calibrate the meat probe? Are you checking internal temperature of the meat with a reliable instant read thermometer like Thermopen or...
That doesn't sound right. The auger should stop feeding pellets if the thermostat reads higher than the set temperature but it does take a few minutes to bun off the excess pellets. I'm not sure how the blower is programmed but it only furnishes combustion air.
Mine overshoots every time, no big deal. During ignition it dumps pellets in the firepot and it takes a while to ignite, then they all ignite. Just open the lid and let it cool to desired temp. It will level out.
ThermoPro TP-19. Very accurate and fast readout. Only cost ~$30.
https://www.amazon.com/gp/product/B07R18W3W1/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1
The last duck I’ve attempted to cook was a total disaster. I hope they are domestics, mine were taken over a farm pond and they smelled like sewage. I haven’t hunted duck since.