is it intended that they can only be used in the player armor because of how much of a jump it is from mk3?
at the point where I'm making them now and I would like to put them in some K2 tank/spidertron grids you see

Hi,
I’m not sure I understand your question.
As for the tank and the Spidertron, they are perfectly able to use this equipment.

yeah it might be a k2 thing from how it handles equipment grids, the personal roboport and personal battery equipment added by this mod can only be slotted into the player armors

I appear to be the k2so issue guy

No problem :)
I think you should report it to K2SO, maybe they can do something.