I love the name Magdalena and I pronounce it the same as you. I don't care for other spellings because they just look off. I've never met anyone with this name, which makes sense considering that for the last two decades it's barely made the US charts, if at all. I guess it entirely depends on where you live. If you live in a place where it's popular and commonly pronounced -layna, then the -lina spelling may be a better alternative.