Illegal/immoral orders can be silently sabotaged and reported later. Look at RF and Belarus. Russians are happy to kill Ukrainians, while Belarussians are wrecking Russian military trains. They received same orders.
Only if the lower echelons of leadership are on board with sabotaging the orders. If they're not that's when you end up taking the "enemy fire" that back authorizes the use of force for the war crime.
Dude, they are illegal and are risking torture and jail of they will be caught. It is underground opposition doing those things.