While there is much more to be said on the subject, the following answers concerning the famous bunker scene in Downfall may be of interest to you:
In pop culture, Hitler is often depicted seething with rage, and almost cartoonishly quick to anger. Is this depiction based on actual evidence and firsthand accounts of his demeanor, or has he been caricatured over the years? with an answer by u/Georgy_K_Zhukov and
How historically accurate is the film Downfall? with an answer by u/kaisermatias