I feel like
Diana is more name-y, if that makes sense, and
Diane is more middle name like. I don't have a problem with it at all but I would prefer
Diana. That said, I knew a nice yet eccentric lady named Miss
Diane some time ago and that's who I think of when I see this name. Because of that association I can't help but think it's more old-fashioned, while
Diana for the most part is pretty youthful but mature. I can still see a young
Diane, but still. Also how can I resist
Diana by 1D and Dirty
Diana? Lol
https://www.behindthename.com/pnl/217493
"It is not in the stars to hold our destiny but in ourselves." - William Shakespeare