Swap the pillowcase before replacing the pillow.
Too high can feel like too firm.
Remove inserts slowly, not all at once.
Check the cover first
A tight pillowcase or stiff protector can make a pillow feel harder than it is. Try a softer or looser pillowcase. If the pillow has a removable outer cover, wash and dry it according to care instructions to see whether the feel changes.
Separate firm from high
A pillow that feels hard may actually be too tall. Extra height can create pressure and make the pillow feel less forgiving. Test a lower pillow for comparison or remove inserts if the pillow is adjustable.
Give fill time to settle
Some pillows soften with use, while others stay close to their original feel. Fluff, shake, or gently redistribute fill if the design allows. If the pillow has a foam core, check whether it is meant to be used with a particular side up.
Use a transition layer
A softer pillowcase or thin folded towel over the pillow can change surface feel for a test night. If that helps, the surface feel was the problem. If it still feels wrong, height or core firmness may be the issue.