It made me dizzy when I first saw it. It's difficult to unravel. And it continues to be difficult, even when I know how it's pronounced; I still get the r and the m mixed up when I try to write it.
The problem with
Mira as a nn is that it doesn't match the pronunciation of the full name (Semiramide/Semiramis). In
Mira, the emphasis goes on the i. This makes things more confusing. I would use the nn
Sem.
For the nn
Mira, I would use the fn Semira, so the pronunciations match.