You can consider simplifying the shapefile via {rmapshaper} - for a possible approach consider this post Shape file maps with Leaflet - #13 by jlacko
It refers to a very similar problem (a very detailed map of administrative units of Brasil).
You can consider simplifying the shapefile via {rmapshaper} - for a possible approach consider this post Shape file maps with Leaflet - #13 by jlacko
It refers to a very similar problem (a very detailed map of administrative units of Brasil).