I read Otto Skorzeny’s book years ago in which he said a commando unit was trapped way behind Russian lines, and were moving to a lake where they were to be picked up by aircraft. They were never heard from again.
Of all the Nazis, Otto Skorzeny is the most fascinating character of all. Even wound up working for The Mosad after the war.
Some time ago I read about a group of Russian-speaking Balts (dressed as Soviet troops) dropped behind the Soviet lines to create mayhem late in the war; I don’t believe any returned.