Do IK Animations affect the way different avatar rigs animate compared to traditional joint moving and rotating?

I’m having some trouble with making animations that look consistent with different kinds of avatars. Poses such as crouching, achieved by bending the legs while keeping the feet in the same spot can be tricky to nail without IK, which unfortunately doesn’t seem to be available in Moon Animator. Even when I nail it with one rig, it falls apart with other kinds of rigs.

This particular keyframe of an animation looks fine with only 2 rigs. Block Rig and Mesh Rig. Every other rig is not in the correct position.

Rhtro Rigs are floating.

Man Rig and Woman Rig are sliding forward.

Because of this, I was considering switching to Blender for a while in order to use IK for my animations, but that made me curious as to whether or not IK would affect how an animation turns out with these varying rigs.

If I were to have an animation where I bent my legs down via IK, would it look right on different kinds of rigs? Or does IK just automatically determine the position/rotation of the current rig you’re animating, and then behave like a standard keyframe with specified position/rotation values after being exported to Roblox?