I guess the problem remains that the legs still don't need to lift the body weight.
For example in a barbell squat, your shoulders lift the bar, but your legs lift that weight plus your bodyweight. In space, bodyweight is not a factor so your legs only have the same load as the shoulders. So upper body / shoulder might end up being the limiting factor, not giving the legs the same amount of load they would under gravity.
That could be solved via a vest that you wear, that has additional cables pulling with a force of the bodyweight. That way you could also do pull ups with your bodyweight.
For example in a barbell squat, your shoulders lift the bar, but your legs lift that weight plus your bodyweight. In space, bodyweight is not a factor so your legs only have the same load as the shoulders. So upper body / shoulder might end up being the limiting factor, not giving the legs the same amount of load they would under gravity.