As for tariffs, yes, it does make the cost of goods higher but if the IRS is done away with and people can spend money that used to be going towards taxes on more expensive goods then the majority of Americans could come out ahead. Especially if DOGE can cut a couple of trillion from the federal budget.
And the other thing that Trump is negotiating with is the culture of the US, to any producer the consumer culture in the US becomes a very attractive market, so Trump threatening tariffs on producing nations is a way to let them know that their product would be so expensive that consumers would simply not buy it, and not only that, their product would leave a vacuum that someone else will step in to fill in.
This leads nations to play by his rules in order not to lose access to that market. It's probably one of, if not the only nation, for instance, where people will rent a car for 4 years, every 4 years. That first vehicle will then get sold to someone else, and so manufactures, financial institutions, service providers, etc, get to make a lot of money from production to disposal.
Without that culture Trump could not negotiate the way he does, and the challenging aspect of it is that for the US to carry on with that culture, the US needs to remain in its current status financially, which is unsustainable. What most Americans associate the greatness of the US with, is their ability to remain capable of being an attractive market.
I used to think that there was only one way for the US to remain the world's leader, and that it was to maintain their mafia style treatment of all their vassals, but I've been recently reading about JFK's presidency, and there is another way, which is what he was attempting to implement, to lead other nations by inspiration and mutual aid not to fall in the misery that would lead them to fall on communism.
I don't think Trump has the philosophical understanding of the principles JFK had, but I do think he has a similar understanding of geopolitical realities, only through finance. JFK's thing was that peace was worth exploring and it was mutually beneficial, Trump's thing (I think) is, if we can do business why would we do war?
And that, even without the philosophical foundation that JFK had, is good enough. It's either that or the current approach which is more along the lines of "you do what I tell you or I'll destroy you, even if it is to self destruct"
