Operation Reinhard (1941) was a codename for the plan to resettle and systematically exterminate the Jewish people. It is important to understand that other camps built prior to 1941, like Auschwitz, had these extermination instalments. Both extermination and work camps were inconsistent in that some had gas chambers using two different chemicals and some didn't. The distinction between "Operation Reinhard" camps and other extermination centers is not clear-cut

There are three major Operation Reinhard camps which were designed to complete this task: Belzec, Sobibor, and Treblinka II. The extermination techniques used here were somewhat different than other camps, where they used Carbon Monoxide to kill their victims. This technique was...more gentle... in that it took a long time before the victim would go unconcious and die in their sleep. This, juxtaposed to using the horrifically painful, but fast-acting, Zyklon B, was relatively "inefficient." Later on, some of these camps adopted Zyklon B to quickly and efficiently kill their prisoners.

SO, TO ANSWER YOUR QUESTION: To clarify: a Sonderkommando were Jewish prisoners who were responsible for putting other prisoners in and gas chambers and taking their dead bodies out, and had a terribly low life expectancy.

A Sonderkommando was, however, more likely to live being exposed to Carbon Monoxide rather than Zyklon B which killed victims incredibly faster.

A prisoner in the Sonderkommando in Birkenau would not live the full period of 1942-44 in all likelihood. There are a few exceptions, and I think given the period you are interested in you should read the memoir and testimony of Filip Muller, who was a sonderkommando in Birkenau from April 1942 until January 1945, and was one of the few survivors of the sonderkommando. You are right that their experiences would be somewhat different. Sonderkommnado in Auschwitz II Birkenau had somewhat more contact with other prisoners than the sonderkommando in the Operation Reinhard camps (Treblinka, Belzec, Sobibor). First off, by 1943 prisoners in the Reinhard camps were noticing transports slow down, and were suspecting that they would all be killed. This lead in both Sobibor and Treblinka to uprisings, which mostly didn't include sonderkommando because they were isolated from the rest of the prisoner population. In Auschwitz Birkenau on the other hand the deportations continued throughout 1943, and in fact there was an enormous uptick in killing in 1944 due to the deportations of Hungarian Jews. In October of 1944 there was an uprising among the sonderkommando in Birkenau. In other ways their experiences, their daily lives, their trauma, and their deaths, were quite similar.