For any one like me who do not have access to gypsum. I have done a (somehow) 1:1 molar measurement of
the two compounds:
water saturated CaCl2 (exothermic)+ water saturated MgSO4 = wet Calcium sulfate

I got a white slurry.

after that i ran the liquid through a shirt, gathered all the ends and closed it make sure there were no holes. i squeezed the water out and got a semi dry putty that can no longer be squeezed in the shirt to dry further (like white clay).

I put it in a plate in a microwave oven with medium heat and waited for it to dry. (checking it every now and then to make sure heat is evenly distributed on the white matter)

after, it is dry and powdery when trying to break by finger. i tried to crush it with a spoon or a mortar and pestle to have smaller pieces like pebbles. reheat 1 last time before placing in an air tight container while still slightly warm to make sure it is still dry when kept.

Can anyone confirm if this is calcium sulfate as the end product? any tests i can do to check this?

What you got is calcium sulphate, well done! There will be slight contamination with calcium chloride and magnesium sulfate which you could remove by repeatedly washing the calcium sulfate slurry with fresh water.