You probably have at least one MIPS device in your house (router or modem). Based on the three architectures you named it sounds like your project isn’t really

You probably have at least one MIPS device in your house (router or modem). Based on the three architectures you named it sounds like your project isn’t really aimed towards embedded systems. But those legacy architectures are dirt cheap, relatively energy efficient, and good enough for most purposes so they aren’t going away any time soon.