Hey there, I’m sorry about this craziness. My comment was not really directed at you, but I was just quoting part of the original post that mentioned you.
I was trying to suggest that OP is confusing criticism of the GrapheneOS community with criticism of the OS. You make a good point and, as I pointed out, you were not criticising the OS, but the community. Not the same thing.
Open Tracks allows exporting in either KMZ (default), KML or GPX format. Go to Settings, tap on “Import and Export” and there look, towards the end, for the entry “Export/sharing file format”.