What i mean by this is that there is not really a colour scheme because everything is a different colour and it looks weird and a little unprofessional.
That'll be the problem mate, 13.2 is weird and glitchly, and dynmap is still in development for it. I would suggest going to the dynmap discord and asking for help there.
You can host a server off your own computer however to be able to do this, you need to portforward your connection. There are plenty of youtube videos on how to do this.