Carol absorbs energy according to that weir art book marvel released, she was created from tessaract energy,meaning like Wanda she should be able to destroy the space stone, space stone was present in the instance of the headbutt,she was basically not a physical threat to Thanos initially,coupled with the fact that she struggled to overpower an extremely injured Thanos at the beginning with help from hulkbuster and war machine.
Yeah makes sense she was absorbing energy from at least the space stone
And why would Clark not no sell a headbutt from Thanos, the Diana headbutt is visually more impressive, Shockwave don't just form accidentally, this was because of power
Are people really trying to lowball the step feat? Hitting someone that hard under that amount of pressure and damaging a column that can resist the depth is more than any hit carol has ever taken. I think even Clark would have felt it. Remove the pressure and it's going to look a lot better