Does this standard apply to Trump?

Sure! I have zero doubt that he is sincere in his conviction that immigration policies are too lax, his belief that tariffs are good economic policy, that being erratic and unpredictable is (on net) a good trait for a head of state to have, and a host of other issues. I disagree with many of his stances, but I credit that he believes that the U.S. has certain problems and he thinks his solutions are good ones.

Sure, after merely being a member of the alliance for the past 70 years. Are defense capabilities built up overnight?

Again, back in 2015 European expenditures on the military were higher than U.S. expenditures in Europe. The depiction of European nations as not contributing meaningfully to their own defense is false. Reasonable minds can disagree over whether they should have larger militaries than they do (given the rise of nationalism on the Continent, I'm not sure that's a good idea anymore if ever it was). But the idea that they aren't material participants in their own defense is false.

Those 39 fighter jets the Germans have will go really far if they're needed, won't they? Ditto their 0 submarines.

Have you looked at who is doing 100% of the fighting in the Red Sea?

Last I checked the Red Sea wasn't in Europe. And considering the last time Germany was really out there with their submarine fleet, I'm kind of glad they don't have any.