Add-on poses should include the hip, usually zeroing it, but not the root - “Genesis” or “Victoria 4” for example. So if you make your placement adjustments using the root rather than the hip the figure should stay put when you apply a pose. The other thing you can do is lock the parameters or the whole node - in DAZ Studio click the little cog on the slider for the translations on the hip, select Parameter Settings, and put a check in the box for Locked at top-right (I would suggest locking only the x and z translations, y may be needed to adjust to keep the feet on the ground).
