Yang has the advantage in H2H combat - i dont exactly see why.
we should not forget that when yang's semblance comes into play, she will already be low on aura from the damage, while sakura is able to heal herself even without using hands - that time when sasori run her through.
tthere is also that she can make an opportunity herself to back away and heal - she has explosives, smoke bombs, sleep bombs, substitution and intellect...
not to mention that she can set up traps, especially given the battlefields. A surprise attack is almost guaranteed.
so when yang will have her semblance working, it will be something like this (fighting game-wise).
yang will have more attack damage (according to this wiki), while sakura will have ~3 or 4 times more health at that moment. so in conclusion, even if yang technically has more attack damage, sakura's hits will still be more dangerous for yang than the other way around.