I had Pretty Pipes installed in my modpack and when I went to add D&E, the game crashed. I checked with the DnE dev who advised the following:

"Pretty Pipes conflicts with DnE because both of us include apfloat but Pretty Pipes' version range for it is incredibly strict and we bundle a higher version, which it refuses to accept and because apfloat is not a mod, you cannot really fix it. it is a library. it doesnt work the same way as mods do where you can override the versions it looks for"

Minecraft Version: 1.21.1
Neoforge version: 21.1.194
Pretty Pipes version: 1.21.0
Data and Essence version: 1.0.0-alpha-song_of_the_factory6

Crash Report: https://mclo.gs/fkomG9Z
latest.log: https://mclo.gs/bkmEPSM