Hitler wasn't elected. He was appointed as chancellor by the president he tried to beat in elections, none of which he ever won with enough of a margin to be elected president. That little bit of pedantry aside, the circumstances and central philosophies (such as they were) of the Hitler dictatorship and factors leading up to it are so different from the circumstances of Trumps presidency that comparing them is mostly crap.
Also, Trump has actually been elected, in a fairly functional, generally working as designed process that did what it was made to do. Whether you like him or not, his winning this election was exactly the opposite of democracy being broken.
It was an affirmation of the process, in which a maverick, newcomer politician was able to win once despite disdain not only from virtually all of the opposition and much of the media but also even from those within the very party he represented, and then later secure a second victory in which he reshaped the political landscape around him and the party that had formerly only grudgingly accepted him. I can't at all see how that's an example of supposed democratic process failure.