just to further improve this, I just found out that after 1.19.51, any worlds in the com.mojang/minecraftWorlds folder that has a space in between prevents you from modifying the world settings. I just found it out but I do not know if I should edit the report or not, so just asa a clarification, I am leaving the comment here
looks like it came back in 1.19.40
For those interested: 1.21.60 and 1.21.80 had a couple changes to the creeper's files. The diffs have been attached.
[media][media][media]the issue seems to be due to “creeper_armour.render_controllers.json” being in a dictionary instead of a list like before. Do look at these files and make your changes because I doubt Mojang would update the creeper textures to fix this 'bug'