A whiner whines, a whinger whinges. Whine and whinge are two separate words.Chaucer spelled words very differently than they are spelled today. Thereās a reason for that.
Adding a āgā to āwhinerā however is not an example of that reason.
A whiner is a person, especially a child, that who complains or expresses disappointed or unhappiness repeatedly.
A whinger is a person who complains or protests, especially in an annoying or persistent manner.
Subtle differences, undetectable if your American.