Wait. I haven’t done anything related to Genshin Impact on here but I’ve been playing it recently. I also don’t think this was directly requested to me because it just says looking for an answer. Quora tracking what I play?
Anyways, it’s very hard to say who’s stronger. They’re both relatively comparable, or at least, the difference between them isn’t particularly large. But Jean has better overall feats than Diluc, who mostly just has scaling and vague statements to go for. I’d also say Jean could probably counter his fire magic in some ways with her wind magic.