

The officers issue orders, and the officers mostly hate Trump. The enlisted people are far more pro-Trump than the people who issue orders. They take an oath to protect the people under their command AND an oath to protect the Constitution, and they take those oaths very seriously. They hate that Trump shits all over those people and shits all over the Constitution.
They will follow orders from Trump when there isn’t much at stake or if they align with their mission of protecting the United States and its allies/interests. I think you would see mass resignations on the officer side of the military if they were commanded by Trump to attack Canada. They might not refuse to follow an order, but they might resign or force a reassignment to a post that is not involved with the attack on Canada.
I work daily sitting next to officers. I think I have a decent idea what they feel about how things are going and what they would do.