I have had the same issue as you, I was using DbGeography.PointFromText("Point(lat lng)")
when the lat & lng arguments are expected the other way around. The complete answer is this:
// From Google, Japan's latitude: 36; longitude: 138
var lat = 36;
var lng = 138;
var location = DbGeography.PointFromText($"Point({lng} {lat})");
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