contact fair or foul

[grizzlierbear]

I find slide tackles that carry through the player after first ball contact or if the trailer leg cuts the feet out of the attacker far easier to judge as dangerous than the angled intercept e.g. (attacker running to the corner with defender moving across)
I have considerable difficulty with player contact between attacker and defenders on fast paced, intersecting, angled runs.
Imagine a hard charging defender attempting to toe away or step in (where contact with the ball is made first) but with devastating effect to the attacker as he falls over the outstretched leg or is knocked to the ground, often quite dramatically by the momentum of the cross angle run. Does contact with the ball first nullify the collision afterwards?
Should tripping or charging fouls apply in these cases regardless of making contact with the ball first? Incidental contact in a contact sport?

I also believe it is nearly impossible for a fair shoulder to shoulder between players of a dramatic height differential. With taller players leaning or pushing down on smaller stature players. In the reverse, the smaller player must jump up at the taller player. Is this a view others share?

If an attacker carries the ball forward and a front facing defender side steps into his path resulting in a same front shoulder to shoulder collision (parties are face to face) monetarily halting the progress of the onrushing attacker what's your call?