yea I definitely agree that python was not the best choice for this little router haha. Originally I was going to try to write the server in GO but was not able to get compile it for openwrt -- so settled for python . I'm not super familiar with writing xmp servers but looks like it could be a good option, will check it:)
you don't need write xmpp server, the point is that it is ready to use and is small in size, the client is also ready, all you need is to choose one and install it