"Battle Royale" conflicts with an Epic IP

Again, this is only as it pertains to the marketplace. You can still use that name elsewhere on Gumroad, CGTrader, Cubebrush, etc. I’m not saying you shouldn’t complain, nor am I defending Epic here for forcing you to rename. Simply saying that by using the marketplace of a private company such as Epic you agree to abide by their rules, provided you are using their marketplace. Elsewhere, you aren’t required to rename your project.