Thank you so much for the pointers! I think I better go again about Animation Boot Camp videos.
I tried the approach to animate actual walking then removing forward animation, the problem is the same as I can’t get feet speed constant (when touching ground) and linear, thus sliding occurs. So I wonder how I should set up my workflow to produce walk loop so that it is not sliding, would like to see how masters do it… I never seen video where the mechanics would be explained regarding this. And yes, that is for game. I just learn and use Makehuman characters for animation so I do not share so no unhealthy questions asked (I can model and rig, but I fail in persistence – I lose motivation completely after mid-rigging and have lots of incomplete characters, so I decided to drop a matter for a few years and concentrate on things I like – coding and animating).