I think that, in the US,
Leah will be lee-uh and not lay-uh at least to 97% of people. If you dislike
Leia, (which I don't automatically think "star wars", but if you do, that's what counts) maybe you can consider alternate spellings.
Here are some possibilities:
Laya / Layah
Leya / Leyah
Leiah - or is that still too close??
I kind of feel that
Leia is the best of all for your pronunciation....