Actually, practically all of the attacks in the Camille fight comes in a pair. If you read over the attack descriptions carefully, you'll realize that there are differences in the startup that correspond to the different attacks that he makes. There is no luck whatsoever, I can assure you.
I have had to restart the fight with Camille at least 10 times, I've tried reading over his attacks again and again and if there is some kind of identifiable pattern to his attacks, I can't find it.
I'm really interested in playing this game, and the prose is very engaging, but I'm tempted to just give up
Since quite a few people seem to be having difficulty with this fight, I posted a guide to the fight on my Patreon. Don't worry, it's not paywalled, it's just long and doesn't really fit in the devlog section. You can find it here: https://www.patreon.com/posts/60210454