UK and Italy are playing Trump’s game. He doesn’t negotiate. He demands tribute and only honours agreements if they are a win for him and he feels like honouring it at the time. Canada has a Trump negotiated trade agreement - the best agreement ever, in his parlance. It is apparently not worth the paper it is written on.
Countries must negotiate trade agreements - with everyone except the USA. And citizens must support their countries by not purchasing any thing from the USA. As for the few Americans that didn’t vote for Trump, so sorry but your fellow Americans still fully support him. So it isn’t “just Trump”, it is America that is the problem. Trump is simply reflecting who the majority of Americans really are.

Except, for example many Canadians, who are really fed up with being the kick ball for American Presidents (Trump has a lot of company when it comes to tariffs), who will do their best to not buy anything from the USA. I predict our trade deficit will go in the opposite direction that Trump hopes. The USA still needs to buy electricity, gas/oil, wood, and various other raw products from Canada. We don’t have to buy finished goods from the USA since there are plenty of other countries to supply them. We really don’t need to vacation there.