The general consensus is to do nothing except brush out mud, dust and grime. Using waterproofing, wax etc changes the finish of the leather drastically. A suede brush/eraser is all you need. That’s the genius of roughout, very little maintennance, even in tough conditions.
I have a pair of roughout Viberg boots in a similar colour to these that I’ve used for three winters, for everything from daily use to mountain hiking. I’m away from home for a few days but can post a pic next week. They look great though.