The US has had two faces for the last generation. Bush jr. dragged the British into Iraq and generally angered the EU. That the next republican president was overtly hostile to the EU is a continuation of the theme.
It’s hard to build an alliance when one of the partners flips their fundamental goals every 4 years.
Bush was trusted in Europe. We never felt that he betrayed Europe. There were tough trade deals and stupid wars, but there was never doubt we could rely on the US in this times. It was fine.
This started with Trump and Project 2025 and whatever the tea party mixes in there.
Both are not friend of EU/Canada right now. But China at least never pretended (or we never saw them like that). The US however was a factual savior, then a close ally and a partner for 85 years! That is roughly 60 years longer than China was a relevant factor in the world order. It is the loss of trust / change which tortures the world. Not the amount of current trust.
Do we know China’s goal better? They seemed quite willing to punt on Hong Kong democracy until 2049, as they originally agreed to, until one day they decided that it was time for democracy to be over.
The US is just less trustworthy at this point, at least we know china's goal better.
Note: both under the current administration