same here! I've substituted the high knees with bicycle crunches because of both the noise and because i felt like o wanted a bit more exercise for my core
I am…. I actually do it exactly the same I didn't try to modify it because I view it as a medium intensity routine yet it is mostly recommended that you modify it in a way that is more appealing to your body ( you don't need to tire your self to the extreme)
At times. I have a bunch of joint issues and when they flare I cannot do step ups, squats, lunges. I replace with those with more core workouts, or I just skip them entirely and do my pt exercises at the end.