Um, the assassination attempt on Hitler was in Summer 1944 - how does this alter the Final Solution ? Wannsee was held on 20 January 1942
It would end the war in a less destructive manner, and certainly save a couple of million lives, many of whom WOULD be Jews, but the Final Solution would still have reaped its harvest up to that point
Its an interesting question what if no Holocaust, for that would assume the Jewish populations of Europe remain in their cities, and that even if an Israel is born it isn't seen as having some sort of divine right to do what it wants, heedless of the rest of the world
On the other hand, tho, anti-Semitism on a lower level may well remain a reasonably respectible view for several more decades, and the idea of a genocide to end all genocides, together with the concept of war crimes, would not exist
Best Regards
Grey Wolf