a site that lists all the germans and austrians soldiers who was killed in WW II, probably does not exist.
A good way to search for dead or missing soldiers is https://www.volksbund.de/home.html
Another good possibility is also http://www.denkmalprojekt.org
There are more than 3.5 million names of german and austrian soldiers, starting with the "Thirty Years' War" 1618-1648 and continuing into the period after the Second World War.
Best regards from Vienna.