During a PhD, what should I do that is not research?
As the comments say, do what you want.

It is your free time. There is no meed to sacrifice it to your PhD. Otherwise you might later end up feeling that you have "wasted" time, as in this question. Your research work seems to be going well, so there is also no pressure to put in more hours. 

There is no need to optimize every aspect of your life. Try out those things you have mentioned, see what works out for you/what you enjoy more. We cannot make that choice for you.