First you could simply use many conditions (each checking for a combination of category and country) and set a variable in the condition body to contain the E-mail addresses as a semicolon-separeted string.
Or you could combine both category and country with a delimiter into a single string variable first and then switch on that.
Or you create another SharePoint List with the columns "Category","Country" and "Emails" (containing the semicolon-separeted email addresses ). Then just query for all rows in that list that match your current "Category" and "Country" and send your mail there.
The method will also make your flow very clean, as you don't need to have complex logic in there. You just query.