Using the following:
Forge 47.3.0
McJtyLib 1.20-8.0.6
RFTools Base 1.20-5.0.6
World Stripper 1.20-3.3.0

These are the only mods present

Go to the End use World Stripper to delete large areas their is no End Dimensional Shard Ore
Kill Ender Dragon throw ender pearl to go to End City area World Strip that area as well no Dimensional Shard Ore

However their is Dimensional Shard Ore found in the Overworld and Nether.

I do not have RFTools Dimensions installed either from my understanding having this mod should only allow Dimensional Shard Ore to spawn in the Dimensions created. I will give this a test as well.

When RFTools Dimensions is installed I still cannot find any End Dimensional Shard Ore just an update to my findings