There are so many good actors running around these days, as evidenced by all the no-name good acting we see on streaming television shows and movies, that if I had been casting for this, I think I would have looked for an unknown (in the U.S., which is usually the initial entertainment target audience) Israeli actor.
Mirren is an easy choice because they knew she'd do a good job and her name pulls in viewers.
But it would have been interesting to see an Israeli actress play this role, too.
But no, I don't think Mirren or anyone else should be limited by her own ethnic background. I'm excited to see Denzel as Macbeth! I haven't got Apple+ yet but that's the first thing I'll watch when I get it.
Also, blackface was a little different. It was a degrading representation of an entire group of people.