I've always wanted a watch whose face colors can be changed to fit my outfit. It seems this is doable albeit at the cost of battery but I havent seen any software that allows it
This is totally doable! The Always on Display screen can have colors and those do not impact the battery life much. Nothing hinders you to show a full color as AoD. There are some watches however that only support 4 colors in AoD mode. Namely the ASUS ones. If you are serious about developing such a watchface, come to our matrix chat for more tips where to start.