polygons – Question about error executing RegionResize of map

I want to resize the map of the country as below.

region = EntityValue[Entity["Country", "SouthKorea"], "Polygon"] /. g_GeoPosition :> g["LongitudeLatitude"]
newregion = RegionResize[region, 10]

However, newregion often stops with no results.
Also, all previously executed information will be erased.

mf = RegionMember[newregion]; mf[{125, 35}]

I want to discriminate the inside and outside of the data with a resized map.
Could the error be caused by the map being disconnected? How can I solve this?