I think this is a lot better than the FK but this animation also has some troubles I think. I did learn that you should pivot around the ball of the foot because that’s the last place that makes contact with the ground. And I was jumping to just see how it feels like to jump and I noticed that my hips were moving back and forth a lot while jumping.
There is too much movement I think. I’m pretty sure this was because keyframes automatically bezier when you make them. I know after effects does this as well. I don’t know how to disable that in blender. But it’s jiggling a lot especially at the top because of this. I tried to fix it just by adding more keyframes but you can still clearly see the jiggle.