Those aren't necc. any less confusing, for someone who doesn't really get to use French much day-to-day. I find modern slang to be a bigger pain than archaisms in an otherwise straightforward sentence, personally, it's just look up that one word and carry on. And if classics are what someone is interested in reading, they're going to be better off just doing that, than something more modern that will have vocabulary and phrasing the older texts won't use while lacking some of those they do.

Harry Potter in French is very straightforward for learners with a lot of useful vocabulary, but think OP is past needing to read that if something else appeals more.