spot dog is hydraulically powered junk, unitree is motor driven from day one. Boston Dynamics was forced to switch to a motor driven architecture after it is proven by unitree.
Perhaps because of the potentially slower actuation speed, but you also generally get a lot more power from hydraulics so im not sure one can claim it is junk. Far less acrobatic, but also far more sumo wrestler.
The Spot dog (which inspired the Black Mirror "Metalhead" episode) in 2016 https://www.youtube.com/watch?v=tf7IEVTDjng
Atlas doing backflips in 2021 https://www.youtube.com/watch?v=FByY3tSx2Ak
So 5 years of progress within a year.