I like
Joanna and
Joan about equally. What puts me off
Joanna is the prospect of
Jo as a nn.
Joanne is the bland one, IMO. And dated.
For
Johanna, I not only pronounce the H, I use the you-HUN-uh pronunciation, which is usual where I live.
I've never seen Johannah, but I'd guess at Jo-Hannah, which I find unattractive.