Zone shading

Is there a way to add shading to certain zones on the map or do you have to make a piece the same shape and have layers? I am trying to have the ability that based on a teams investments they can make a country be pro American or pro Russian. Depending on which way they lean the zone would change shaded red or shaded blue (with high opacity so you can still see the map).
The zones are custom drawn since countries aren’t hex lol so I was hoping there was a way to shade them rather than trying to make shapes match exactly to the map