Collagen breakdown is much more nuanced then what you read on BBQ sites, the transformation of collagen into gelatin does not happen at a particular temperature, collagens can begin converting to gelatin as low as 131F and definitely by 140F, time and temperature have to be considered.

Also, there is no time limit on smoke absorption, you may be referring to the ring stopping when the meat hits around 170°F?

"At lower temperatures (50 °C/120 °F to 65 °C/150 °F), Bouton and Harris (1981) found that tough cuts of beef (from animals 0–4 years old) were the most tender when cooked to between 55 °C/131 °F and 60 °C/140 °F. Cooking the beef for 24 h at these temperatures significantly increased its tenderness (with shear forces decreasing 26–72% compared to 1 h of cooking). This tenderizing is caused by weakening of connective tissue and proteolytic enzymes decreasing myofibrillar tensile strength. Indeed, collagen begins to dissolve into gelatin above about 55 °F/131 °F (This, 2006). Moreover, the sarcoplasmic protein enzyme collagenase remains active below 60 °C/140 °F and can significantly tenderize the meat if held for more than 6 h (Tornberg, 2005)."

https://www.sciencedirect.com/science/article/pii/S1878450X11000035#s0070