I'm not a "Trump supporter" per se, but I do agree with his disrupter role especially slowing down/derailing the globalist agenda here in America. So, I guess that makes me a "nationalist"

I prefer Patriot. Better than the opposite, which is a globalist??
As you know, MAGA is a theme, a campaign slogan, something for those who hold certain TRADITIONAL American ideals/visions to rally around. MY points in recent history when America was it's great-EST from an optimism, growing view? Post WW2 1950s, 1980s under the Reagan years.
What I think Trump is referring to is when American companies were PRODUCING quality tangible goods, providing an elevated wage over much of our current service level jobs. He has stated many times he wants "America first". Would you prefer America second, third, last?
Regarding being OK with your taxes covering others' medical care: The government, especially the federal government is an inefficient distributor of funds. It would be much more productive, and probably be more satisfying to you, to donate to a local shelter or medical provider than sending it to a federal bureauracy. See, that would be of your own volition. What the socialists propose is CONFISCATING money from unwilling citizens who are producing and transferring to others.
When government intrudes on a market, prices go up. Housing, college, healthcare.