This is one of the reasons I think the ab is hard armor.
In my opinion it makes no sense to have a kidney plate and ab with soft material. Thinking about the character, it would be a weak point for him. And thinking about reality, the suit would not look very good.
If there was no kidney plate, as in other versions of the character, it would be very different, I would buy the idea that it is soft material.
But again, it's just my opinion.
To follow the standards, and knowing this armor is a TK armor. it would be good to maintain that requirement.