Using /enchant or an anvil, the mace can have sharpness on it, even in survival mode. In 24w13a-1.20.6, this was not possible. This bug was introduced in 24w18a, with no documents changes on this. According to the 24w13a changelog:
These existing and new enchantments can now be applied to the Mace:
- Mending
- Unbreaking
- Smite
- Bane of Arthropods
- Fire Aspect
- Curse of Vanishing
- Density
- Breach
- Wind Burst
with no mentions of sharpness in this or any changelog after this.
Steps:
1. Open a world with Update 1.21 enabled in 1.20.6, and grab a mace.
2. Head over to the anvil or use /enchant to try and put sharpness on the mace. Observe that you cannot do that action.
3. Upgrade the world to 24w18a or later and re-try step 2.
4. Observe that you can now do this action.
Not fixed in 1.21 Pre-Release 4
Edit : my bad I was in creative mode (guess it's WAI)