I think it's wrong to think of alliances between nations as friendships between people. I'm basically a globalist, I'm in favor of international trade, good relationships etc
But realistically, those are determined by contracts and treaties which are signed by chancellors and presidents or voted on by parliaments, according to mutual self-interest.
To ask citizens in Switzerland how they currently feel about the US and Trump and to observe an X% drop in popularity says next to nothing about our relationship to Switzerland. European nations sometimes rely on trade with Saudi-Arabia (arms) and Russia (oil) and have somewhat normalized relationships with those countries even though their citizens think very poorly of the leaders of those nations, far worse than they think about the US or Trump.
The safest way to be popular in Europe would certainly be to implement policies which are popular in Europe....
Then most people would look at the US or Trump and say yeah that makes sense, seems like a reasonable guy. That's not what he was elected on though.