I have zero belief that any units will ignore or slow walk any orders. There’s just no history of that happening in recent US military existence to expect it to happen now. Vietnam saw a handful of cases where people likely killed their commanders, but it very plainly didn’t impact the course of the war.

The UN will never determine that the US is engaged in an illegal war. The security council needs to vote on that, and the US gets to veto. The ICC doesn’t apply to the US because we never ratified the agreement. It’s just someone elses laws.

Direct action against the military is more likely to have an effect, but linking arms is not going to be effective. Impeding military production is just going to get you beaten and arrested, at best.
Specifically interfering with military operations is particularly illegal and carries penalties way worse than the usual you get for messing with other businesses.
If you’re going that far, at least do something effective rather than slowing down a truck for a few hours.
Look to the WW1 protests, and what was effective there and what happened.