As a former corporate editor, I used to contribute edits specifically to this country for a time. From what I remember, my former boss said there was one guy who added the Romanized names en-masse. If I remember correctly, it was a dude from the UK that liked to vacation there (but don’t quote me on that. That may not be correct). I remember myself and another colleague reaching out to discuss adding Greek names as the default name value (with help from the local community wherever possible) where they could be verified (using Mapillary mostly), but the effort fizzled out. I was bummed out, but it was a good decision, because such efforts are best lead by the local community, not a corporate entity many thousands of kilometers away.
There was also a guy who added fictional roads (like fictional trunk roads) all the time, which caused a major headache for obvious reasons, and that was considered more of an issue/priority to remedy/work on than the romanized greek names.