Since Minecraft 1.19.1-pre6, the xp from Sculk Catalysts have been reduced. Instead of dropping 20 xp per catalyst, each catalyst now only drops 5 xp, or the same as a Sculk Sensor or Sculk Shrieker.

Some farms and players were used to the catalysts dropping 20 xp each, as it provided a good reward for the challenge of killing a Warden not once, not twice, but hundreds to thousands of times via a fully-automatic setup.

To rectify this, a new int rule xpPerSculkCatalyst should be added to Carpet or Carpet Extras, whose value is the amount of XP a Sculk Catalyst drops when broken without Silk Touch.

xpPerSculkCatalyst

Set the amount of XP a Sculk Catalyst drops when broken without Silk Touch.

• Type: Integer
• Default value: 20 (5 in 1.19.1-pre6 or later)
• Suggested options: 5, 20
• Categories: FEATURE, EXTRAS, (TBD)
• Additional notes:
  • You must choose a value from 0 to 2³¹-1. Note: High values may cause lag.

I just found a one-mixin mod that does the same thing; here is the exact mixin:
https://github.com/NikitaCartes/BuffedSculkCatalysts/blob/master/src/main/java/xyz/nikitacartes/buffedsculkcatalysts/mixin/SculkCatalystBlockMixin.java

Feel free to use it as an example when implementing the carpet rule.