Root required, make changes to the data indicator and other indicators on the status bar (visual only) via CSC Feature on any rooted Samsung Device. This does not tamper with the functionality of the device, this is done just for the aestetics.
Configure it whenever you want, pre-boot or while customising or developing a new Samsung Based ROM, I think both OneUI and TouchWiz will be able to use the same method.
Do it at your own risk, and KNOX will be tripped because of rooting.