If you really want the B pin of the Greater Equal node to be byte type, you can just right click on the pin that has 0 value assigned to it and select the To Byte option. (You can also drag out of the bluish green output pin of your variable, release it on an empty space, search for “To Byte” on the menu that pops up and hit enter to get that converter)
But if your code isn’t working as you expect, that’s not the reason for it.