God, I’ve been watching a lot of 40k lore videos for some reason and I can’t imagine the carnage even a handful of Astartes could cause. The Death Star would be annahilated by, like, three dudes.
I would watch two Astartes race through a destroyer. They both board at the nose of the destroyer and have to clear a path to the bridge. First one to shatter the windows and space the bridge wins. It would be a fun contest for the bröthers, and an absolute horror show for the troopers.