So,Black Panther was basically Trump at first with Putting Wakanda people first and not letting in "foreigners"?

Uh, if that’s how you want to interpret it i guess (let’s forget about the film’s conclusion and mid-credits).

And Black Panther, unlike that fool, actually has a heart and helps those who need help. He is the total opposite of comrade Donnie.

The last time I saw a Trump analogy got made about a movie on the internet was for The Angry Birds Movie. Anything can become politicized, I suppose...

And in the end they concluded they were wrong to feel that way. And instead of shutting the world out they would help the less fortunate

The main theme of the movie is about T'Chala dealing with Wakanda's role in the world... The different contenders for leadership had very different perspectives...

T'Chaka (the father) was isolationist, Killmonger wanted to export revolution in a domino theory manner and T'Challa was trying to navigate this, while coming to terms with his family's darker secrets... There were supporting factions and other perspective from the side characters as well (e.g. the niave technologism of the sister and Nakia's perspective that Wakanda has a moral imparitive to better the world, opening boarders etc...)...

Ultimately he decides to have some positive outreach into the world... Having realised that simple isolation ended up with risking his throne and embrioling Wakanda in global war...