So, while this has nothing to do with Monarchy, I do have some Flag Design Proposals I made on Canva. Keep in mind it's different from the American Flags of the past for a good reason. I replaced the blue with the Black for one reason: The black on some flags means Determination and on other flags, it symbolizes The Overcoming of the darkness of past times, and I do believe that it should be the meaning of this flag and the United Kingdoms of America. You might not like these designs, but it's just what I have in mind.
I might need some criticism on these flags because while the Red, White, and Blue of the American Flags do represent History, I do believe the red means British Heritage, Courage, and Strength, white means Purity, Freedom, and Honesty, and black (like I stated before) means Determination and The Overcoming of the darkness of Past Times. These are just what I have in mind, and I hope you might like some of these designs If you don't, that's ok and it gives me an advantage to remake the flag.