Literally every sentence you wrote is wrong.

The worst crimes of the holocaust were a conspiracy within the Nazi government.

This is not true. The Holocaust was ordered by the popular leader of the German government; they were executed by a very large number of people, probably >90% of whom actively cooperated and almost none of whom tried to stop the Holocaust. (see e.g. Christopher Browning's Ordinary Men) German society as a whole knew that their government was attempting genocide; see e.g. What We Knew for supporting details, or Wikipedia for a summary.

(It is at least not totally impossible that the gas chambers were unknown to the broader German public. But the idea that gas chambers are representative of the Holocaust is a historical myth; most victims of the Holocaust were not killed by gas.)

The Nuremburg trials had testimony from an investigator who was attempting to prove his suspicions of these practices, and ultimately prosecute the offenders who were killing the Jews.

This is wrong. (This is kinda a refrain; your Nazi apologia is lacking in sources or historical accuracy.) I assume you're referring to Georg Konrad Morgen; if so, he did prosecute the people killing the Jews, but not for the genocide; he said, correctly, that the Final Solution was 'technically legal'. His prosecutions instead focused on the ordinary crimes (e.g. corruption).

It is likely that only a few hundred Germans were directly involved.

Again, this is just flat out wrong, in a way that shows that you have no idea what you're talking about. Auschwitz alone had ~7,000 camp guards during the war; there were around 55,000 concentration camp guards total. Again, I suggest that you read Ordinary Men, about the ~500 men of Reserve Police Battalion, who killed an estimated ~38,000 Jews. (There were about 17,500+ members of the Reserve Police Battalions, plus another 3,000+ members of the Einsatzgruppen.) There also numerous other SS/Ghestapo/Wehrmacht personnel directly involved beyond the three specific groups I've named.