That most likely is a valid assumption, in re the highest level of command. I am thinking more in local terms; local as in where you and I and millions of others can be found.
Perhaps the more important distinction is the percentage of the officer corps that naturally supports the pro-left, lawlessness of the present administration. How badly must the admin misapply the laws and the Constitution before the oath the officers took to support the Constitution kicks in.
Would suspending elections, for the first time in history trigger a response?
I am confident that most realize there is no law or authority, or even unforeseen circumstance, that allows one to continue to occupy the Oval Office at the end of 8 years.
It sound "nice" to think that there would be a substantial amount that would uphold the constitution, the reality is that soldiers are more beholden to each other. Brothers In Arms.
What you're suggesting would have to be a well coordinated effort. The majority might see the lawlessness, but will not do anything, simply because they need to be a cohesive unit.
We'd all like to think our military is this great, awesome and upright entity. The reality is that it is a organization of individuals, bound together by one thing. NOT the Constitution, but the fact that they are a military unit.
The military does not give orders to the government. It takes orders from the government. It's one thing for officers to get orders and not pass them down. The subordinates don't know anyway. BUT for the officers to go against the government, that will cause fractures in the chain. Many will just refuse.
What you propose is wishful thinking.