Alt+Ctrl+M (Load last Curves) no longer works

If you go to Image > Adjustments > Curves, what shortcut is displayed on the right side?

I didn't understand your question at first. After checking it seems you are right, Levels works as expected Curves does not even after reseting preferences. Ps version 24.5.0

It's still working for me, but I always use an adjustment layer, which is non destructive.