I get the sneaking suspicion somebody is going to try making a sharp politically partisan comment.
I want to say this up front. No matter which side you want to attack with your reference, all politicians are realistic in my perspective. Their motives are messy, the only unrealistic appearances we get about any of them is from media spin and a lack of information that we are being given.
Ok, actually, on second thought... I am now going to give an exact contradiction to my earlier statement using a different take on the exact same reasoning.
The reasoning... what we see from politicians is not the real person. What we see from them is a false impression they are trying to give to the public combined with lies and misinformation given by other politicians and the media combined into a single demonic mechanism. (I don't care what you want to say, this applies equally to all politicians regardless of their political leanings.)
The new take on all this... isn't what I just described above the literal definition of a "character?" Politicians may be real people at home, but they are not real people when they are appearing before the public. They are a real person playing the role of a character. And, also going by the explanation I just gave above, every single last one of them are unrealistic.
Now, there is just one question. US presidents. Trump is the single most demonized president to ever exist. He was slandered to absolutely ludicrous levels. Obama is the most built-up and praised president to ever exist. They sung his praises to the high-heavens. Literally. Some even called him the second coming of Christ. These messianic claims attributed to him got so bad he had to jokingly dismiss them publicly on TV by saying he was born on Kripton, not a Manger.
So, given that extreme dichotomy, which one is more unrealistic? I'm having a tough time making the call between them, but I would have to say the most unrealistic character has got to be one of these two men.