It did convert. Medusa placed Iso in charge - but only as a stopgap. The intent was to hold elections, though that got postponed due to Secret Empire. Iso's still in charge (shown in the Marvel Rising comic a few months ago), so maybe she won that election and is now President of Attilan. No actual title has been mentioned for her, as her appearances since IVX have been few and far between.
Medusa is now Commander Medusa instead of Queen Medusa, she and Black Bolt are basically military leaders, no longer involved in politics.