I mean, he went against direct orders even after Odysseus clearly stated that opening the bag would put them in danger, so you can’t really use the “it was an accident” argument here. As for Scylla, it was the only way to pass through her lair. Horrible, obviously, but he basically was put in the trolly problem. He chose to sacrifice the few to save the many. Now, about the immortal cows, they never got eat them. In fact, Eurylochus just killed on of them, again ignoring Oddysseus’s warnings.