Trump realised some time ago that the European economies are generally screwed and their leaders mostly part of the globalist club whose instincts are all personal self protection.
It matters not at all what the personal relationships are on an individual basis.
Trump knows that the USD is mightier than the gun so to speak, he can push trough his agenda using economic weapons. He needs to balance the interests of US business at the same time which is tricky.
Like him and his methods or not, he is generally effective.