I do not know of a documentary that is 100% accurate, there are some things you can look up for research though:
1. Hitler's speeches.
2. Hitlers, Josef Goebbels etc. writings.
3. Adolf Hitler the greatest story never told (again not 100% accurate)
4. there are plenty of videos on platforms like Bitchute that are an interesting watch.
5. Mein kampf.
There is also plenty of good material to be found in
Satan's library, most of the above can also be found here.