Here is where I differ when you on Trump and some of the analogies that you've made:
Trump doesn't hate illegals. He hates that they have full, unvetted access to our country.
Hitler sought to make the Jews scapegoats. The Jewish communities were flourishing, on their own with no social services. The average Jewish family was better off, on the own accord, than the average Jewish family. That is very different than the illegal immigrants coming to the US and receiving benefits that the average American does not. Some states, Such as Whitmer's Michigan, offers $500. a month (Tax payer funded) subsidiarity to land lords who rent to immigrants over American citizens. The list is quite long. But, the bottom line is that no one wants to torture and kill illegal immigrants. Trump is not advocating for that. Far from it. The message is to stop coming to the US illegally and return to your country of origin if you do not have documentation to be here. Trump is advocating for illegals to be returned to their countries, on the US's dime, safely and responsibly. Again, far cry from the horrors of the Holocaust.
So, Trump dabbled in being a reality show star and Hitler wanted to be an artist. That makes them alike in a meaningful way? Do you have any idea how many people are working as a programmer, attorney, school teacher, grocery store clerk...whatever it may be...and would rather be doing something else? Just think about all of the struggling musicians that have day time jobs to keep their bills paid.
What is wrong with being a Nationalist? I have to disagree that Trump is an "Extreme" Nationalist? He isn't seeking to harm other countries or take over the world. He advocates for America first, in America. Everyone should feel that way about whatever country they are in.
I will stop there with the list of comparisons as I think you get my point. We could pick any two people and find similarities of some kind. It doesn't mean they are capable of the same type of behaviors.
As far as the difference between justice and vengeance, yes, I very much believe there is a difference. Vengeance would have someone harmed because they did something wrong to you. Justice would be seeking they be held accountable to the same standard of the law as anyone else. Beyond that, it is protection our justice system for everyone, not just people in the spotlight.
At the end of the day, I believe that Trump truly wants to do a good job and be remembered as an exceptionally good President. Whether that is coming from his ego or true heart for the American people, is up for anyone to decide. As long as he does a reasonably good job at running our country well, I'll be happy.
PS: That is lousy about Kennedy Jr. Maybe he saw he couldn't win and caved into pressure as not to further alienate himself from his family and peers. I've always detested the family and wondered how so many Americans could worship them. Teddy' a Senator instead of serving time in jail? Too much! But Kennedy Jr. stood up and spoke out against our horrible government agencies. He called corruption that where no one with a voice has done. What he said about the FDA, Fauci, vaccinations and quality of research going back to HIV, was music to my ears. Too bad he either wasn't sincere or didn't have the integrity to stand up to the pressure. He has flip flopped and back peddled other issues he had impressed me with as well.