Some movement at the passenger side's cv axle

Depends on how much axial movement. The CV stub is held in the side diff gear by a spring ring, by design there is some mm's play there. if it's a lot, then sounds like spring ring failed.

driver side spline shaft is held tight by the bearing at the end of the diff. , so no movement

the short side has no bearing. only held by the fit in the side gear splines. known weak point, in my steel diff swap i am adding the suzuki upgrade