Adjusting Bread flavor
Considering the amount of flour used, the basic bread proportions are:


Water: 60% the weight of the flour. Of course this percentage may vary among the different recipes (even above 100%).
Salt: 2%
Fresh yeast: 1%


It may seem a tiny amount of yeast, but the trick is that in order to make bread, you just need time. Time for the yeast to do its job. If you leave the bread to rest for a while (a couple of hours or even more in a banneton before putting it in the Dutch oven) you will get a better rise and flavour. Also, as Stephie said, use very good quality flours. Both things combined and you're done. No need to add sugar, fat or other things.

If you do not have the time, adding more yeast will reduce the resting (and rising) time, but the bread will get less flavour. But if your bread is going to be very hydrated (as it seems), I would really recommend to have patience in the process of kneading and letting rest the bread before cooking it.