My niece's name is
Mara, pronounced with what you call the "map or mat" pronunciation. However, my stepmother persisted in pronouncing it MAHR-uh. When my niece was a baby, my sister (
Mara's mother) said she didn't mind our stepmother pronouncing it that way. She said the pronunciation didn't bother her. So I said I would pronounce it MAHR-uh. This was during a week-long trip that my sister,
Mara, my two kids, and I were taking together. But after one day of hearing me say "MAHR-uh", my sister told me to stop, lol. I've never pronounced it that way since.
Anyway, I don't think that any of these pronunciations are correct or incorrect.